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Batted ball

A batted ball in baseball is a pitched ball that has been struck by the batter using the bat, distinguishing it from a thrown or untouched ball in the rules of play.^[1] This contact initiates various outcomes, including fair balls that enter play and foul balls that do not, with the ball remaining live until it is caught, deadened by a rule violation, or otherwise ruled out of play.^[2]^[3] Batted balls are central to the game's dynamics and statistical analysis, as they determine hits, outs, errors, and advances for runners.^[4] In modern baseball, advanced tracking systems like Statcast measure batted ball characteristics such as exit velocity (speed off the bat) and launch angle (trajectory relative to the ground), enabling deeper insights into performance.^[4] These metrics classify batted balls into categories that influence outcomes: ground balls (launch angle below 10 degrees, often resulting in groundouts but occasional infield hits), line drives (launch angle 10-25 degrees, with high batting averages around .630 due to difficulty in fielding), fly balls (launch angle 25-50 degrees, prone to outs but potential for extra-base hits), and pop-ups (launch angle above 50 degrees, nearly always outs).^[5]^[4] The distribution of batted ball types—expressed as percentages like GB% (ground ball rate), LD% (line drive rate), and FB% (fly ball rate)—is a key sabermetric tool for evaluating hitters and predicting success, as line drives correlate strongly with higher on-base percentages while excessive ground balls limit power.^[5] Fair batted balls that elude fielders can become singles, doubles, triples, or home runs, with home runs occurring when a fly ball clears the outfield fence in fair territory.^[2] Conversely, foul balls count as strikes (except on the third strike) and do not advance runners, often prolonging at-bats.^[3] Understanding batted ball profiles helps teams optimize strategies, such as encouraging launch angles for power hitting in the launch-angle era of baseball.^[5]

Fundamentals

Definition

In baseball, a batted ball is defined as any pitch that comes into contact with the bat held by the batter and is subsequently propelled either fairly or foully. This contact must occur while the batter is legally positioned in the batter's box, as specified in Major League Baseball (MLB) rules, ensuring the play advances under standard conditions. The resulting motion puts the ball into play, allowing fielders to attempt outs or the batter to potentially reach base, distinct from scenarios where the pitch is untouched or intentionally avoided.^[6] For the contact to qualify as a legal batted ball, the bat must conform to MLB specifications outlined in Rule 1.10, which mandates a smooth, round stick made from a single piece of solid wood, with a maximum diameter of 2.61 inches and a length not exceeding 42 inches. The handle portion, up to 18 inches from the end, may include grip material for better control, but no experimental, laminated, or unapproved designs are permitted without certification from the Office of the Commissioner. These requirements ensure uniformity and safety across professional play.^[6] Batted balls are differentiated from other forms of ball contact, such as a foul tip, which is a specific batted ball that travels sharply and directly from the bat to the catcher's glove and is legally caught, counting as a strike while keeping the ball in play. In contrast, events like catcher interference—where the catcher or another fielder hinders the batter's swing—prevent a batted ball from occurring altogether, resulting in the batter being awarded first base without liability for being put out. Additionally, pitches not swung at or intentional misses do not produce a batted ball, maintaining the distinction from strikes or balls in the count.^[6]^[7] The concept of a batted ball has evolved within baseball's rules since the 19th century, originating in the early codified guidelines of the National Association of Base Ball Players in the 1850s and refined through subsequent leagues like the National League founded in 1876, where initial focus was on basic contact and fair-foul distinctions without modern trajectory classifications.^[8]

Fair and Foul Determination

In baseball, foul territory is defined as the area of the playing field outside the foul lines, which extend from home plate through first and third base to the outfield fence and perpendicularly upward, including the foul poles as boundaries.^[9] Fair territory encompasses the space within these lines, forming the playable area for determining the status of a batted ball.^[2] A batted ball is classified as fair if it settles on fair ground between home plate and first base or between home plate and third base.^[9] It is also fair if it bounds past first or third base while on or over fair territory into the outfield, touches first, second, or third base, first falls on fair territory on or beyond first or third base, or touches the person, clothing, or equipment of an umpire, player, or any foreign object while on or over fair territory.^[9] Additionally, a batted ball is fair if it passes out of the playing field in flight while over fair territory, such as over the outfield fence at a distance of 250 feet or more from home plate.^[9] The foul lines and foul poles themselves are considered fair territory.^[2] Conversely, a batted ball is foul if it settles on foul territory between home plate and first base or between home plate and third base.^[9] It is also foul if it first contacts a fielder while in foul territory, bounds past first or third base while on or over foul territory, first falls on foul territory on or beyond first or third base, or touches the person, clothing, or equipment of an umpire, player, or any foreign object while on or over foul territory.^[9] Other foul classifications include a ball that goes directly from the bat to the catcher's body or equipment without being caught in the catcher's glove, touches the batter's person or clothing in the batter's box without being hit fairly, or touches a runner or umpire on foul ground before passing a fielder (unless the fielder has already had a reasonable opportunity to field it).^[9] A batted ball that first contacts the field between home plate and first or third base is foul unless it subsequently bounces over or directly contacts the base or passes the base in fair territory.^[3] Umpires determine fair or foul status in real time based on the ball's position relative to the foul line or pole when it first touches the ground, a base, or a player, rather than the fielder's position.^[9] Since 2014, Major League Baseball has allowed instant replay reviews for fair/foul calls, particularly those near the bases or involving boundary disputes, to assist umpires in making accurate judgments.^[10] Edge cases include batted balls that go over the outfield fence in flight in fair territory, which are ruled fair and result in a home run if the distance is 250 feet or more from home plate, while those that bounce over the fence are ground-rule doubles.^[9] If a batted ball strikes a foreign object, such as a batting helmet, while on foul territory, it is immediately classified as foul and dead.^[9] Balls caught by a fielder in foul territory before touching the ground are also foul, regardless of the catch's validity for an out.^[3]

Effects on Gameplay

When a batter contacts the ball in such a way that it becomes a fair ball, the batter immediately becomes a runner and is entitled to advance to first base, with the potential to reach further bases depending on the ball's trajectory and fielding response.^[6] Fielders must then attempt to put out the batter-runner or any advancing baserunners through tags, force plays, or catches, which can result in hits if the batter reaches base safely, errors if defensive misplay allows extra advancement, or multiple outs such as double plays on ground balls to infielders.^[6] Runners already on base are forced to advance ahead of the batter-runner and may score on successful hits or errors, directly contributing to run production.^[6] In contrast, a foul ball counts as a strike against the batter for the first two strikes, but does not advance runners unless the ball is caught by a fielder, in which case runners must retouch their bases before advancing at their own risk.^[3] If not caught, the foul ball renders the ball dead, halting play until the next pitch, and runners return to their original bases without any opportunity for advancement.^[6] With two strikes already accumulated, a foul ball remains live in play, but the batter cannot be called out on a third strike solely from contacting the ball; only a swinging miss or uncontacted pitch outside the strike zone can end the at-bat in that manner, allowing the foul to prolong the plate appearance indefinitely.^[6] Strategically, foul balls enable batters to extend at-bats by fouling off pitches, which increases overall pitch counts, fatigues pitchers, and rewards patient approaches that work deeper into counts for better hitting opportunities.^[11] Fair balls, by driving offensive action, play a central role in scoring runs through base hits and advances, fundamentally shaping game outcomes and team strategies focused on manufacturing rallies.^[2]

Classification by Trajectory

Fly Balls

A fly ball in baseball is a batted ball that travels high into the air with a significant arc, propelled primarily upward before descending toward the field, distinguishing it from flatter trajectories like line drives or ground balls.^[12] According to Major League Baseball's Statcast system, fly balls are categorized by launch angles between 25 and 50 degrees, where the angle measures the vertical direction of the ball off the bat relative to the horizontal plane.^[13] This arcing path results from backspin imparted by the bat, which helps maintain lift and prolong the ball's flight.^[14] The distance and hang time of a fly ball depend on key physical factors, including exit velocity—the speed at which the ball leaves the bat—and environmental conditions like wind and altitude. In MLB, the average exit velocity for fly balls is approximately 95 miles per hour (as of the 2024 season), enabling typical distances of 300 to 350 feet, though elite power hitters can exceed 400 feet under optimal conditions.^[15] Hang time, or the duration the ball remains airborne, often ranges from 3 to 5 seconds for standard outfield fly balls, providing fielders time to track and position themselves but also increasing the risk of errors if misjudged.^[16] Fielding a fly ball primarily involves outfielders, who adjust their positioning based on the batter's tendencies, pitch location, and initial trajectory to intercept the descending ball. Outfielders employ techniques such as reading the ball's launch angle and spin to predict its landing spot, often backpedaling or charging forward to make the catch over the shoulder or above the head.^[17] A caught fly ball typically results in an out, but under the sacrifice fly rule, if there are fewer than two outs and a runner on third base scores after the catch, the batter is not charged with a time at bat, recognizing the strategic value in advancing runners.^[18] Historically, strategies surrounding fly balls evolved markedly from the dead-ball era (roughly 1900–1919) to the live-ball era (1920 onward). In the dead-ball period, low-scoring games emphasized "small ball" tactics like bunts and hit-and-run plays, with hitters avoiding high fly balls due to the softer, less lively baseballs that limited power and increased the likelihood of routine outs by deeper-positioned outfielders.^[19] The transition to the live-ball era, prompted by rule changes such as banning the spitball and introducing cleaner, wound-tighter baseballs, encouraged hitters to adopt uppercut swings aimed at elevating the ball for extra-base hits and home runs, shifting defensive strategies toward shallower outfield alignments to counter the increased fly ball distance and frequency.^[20]

Ground Balls

A ground ball occurs when a batter strikes the ball such that it contacts the playing surface immediately after being hit, resulting in a rolling or bouncing trajectory primarily along the infield or into shallow outfield areas. This type of batted ball is characterized by a low launch angle, typically under 10 degrees, which distinguishes it from higher-trajectory hits like line drives or fly balls.^[21] Ground balls can vary in their initial path: "choppers" are struck downward, producing higher, more unpredictable bounces, while "rollers" skim the ground with minimal elevation, allowing for smoother travel across the field.^[22] The speed and bounce of a ground ball are significantly influenced by the field surface and conditions. On grass, the ball experiences greater friction, which slows its roll and reduces distance compared to dirt surfaces, where harder-packed soil can accelerate the ball post-bounce depending on the exit velocity and terrain firmness. Soft or uneven dirt, however, may cause deceleration or erratic hops, complicating fielding. These variations affect playability, with infielders adjusting their positioning and glove work to anticipate bounces on mixed grass-dirt transitions common in baseball diamonds.^[23]^[22] Defensively, ground balls demand quick reactions from infielders, who field the ball to record force outs at bases or initiate double plays, such as the common 6-4-3 sequence where the shortstop (6) throws to the second baseman (4) covering second base, who then relays to first base (3). Errors occur more frequently on ground balls due to the short reaction time and variable bounces, but modern strategies like defensive shifts reposition infielders—often overloading one side of the infield—based on batter tendencies to convert more grounders into outs. These shifts have increased double-play opportunities against pull-hitting batters, though they risk allowing hits to the opposite field.^[24]^[25] From an offensive perspective, ground balls generally offer limited value, frequently resulting in groundouts or, with runners on base, ground into double plays, which suppress scoring potential. They produce hits, typically singles, at a rate of about 23% (as of the 2024 MLB season)—higher than fly balls but with negligible extra-base power, yielding a weighted on-base average (wOBA) around .213 and just 0.05 runs per out. This low slugging potential makes ground balls less desirable for power hitters, who prioritize elevating the ball for greater distance and run production.^[26]^[27]

Line Drives

A line drive is a batted ball struck sharply by the batter, traveling in a relatively straight line with minimal arc and high velocity, distinguishing it from higher-arching fly balls or low-bouncing ground balls.^[28] In Major League Baseball (MLB), line drives are classified by Statcast as those with a launch angle between 10 and 25 degrees, resulting from solid contact that propels the ball efficiently through the air.^[21] These batted balls typically exhibit exit velocities exceeding 95 mph for hard-hit examples, contributing to their reputation as one of the most productive outcomes for hitters. The travel path of a line drive follows a near-horizontal trajectory, allowing it to cover distances of approximately 250 to 280 feet in about 3 to 4 seconds with little vertical drop, making it challenging to intercept before it reaches the outfield.^[29] If not caught, the ball risks skipping off the outfield grass or wall upon landing, potentially turning into extra bases.^[28] This straight-line motion maximizes distance relative to air time compared to other batted ball types, often landing in fair territory for optimal offensive advantage.^[5] Fielding a line drive presents significant challenges due to its speed and low flight path, particularly for infielders who must react instantly to prevent base hits.^[28] Infielders often struggle with the rapid approach, requiring precise positioning and quick dives, while outfielders frequently execute spectacular robber plays—diving catches that steal potential hits—or charge in for low liners.^[30] These defensive demands highlight the line drive's difficulty, as even elite fielders can be tested by its velocity and minimal hang time. Offensively, line drives offer the highest potential for extra-base hits among batted ball types, with a league-average batting average on balls in play (BABIP) of around .685 and a slugging percentage of .937 in recent MLB seasons (as of 2024).^[5] They generate 1.26 runs per out, far surpassing fly balls (0.13) or ground balls (0.05), often resulting in doubles that drive in runs and advance baserunners.^[5] This efficiency makes line drives a key component of sustained scoring rallies, as approximately 73% convert to hits, including frequent extra-base opportunities.^[31]

Pop-ups

A pop-up is a type of batted ball in baseball characterized as a fly ball with a high launch angle, typically exceeding 50 degrees, resulting in a short trajectory that lands within the infield, often under 150 feet from home plate.^[21]^[32] These balls are usually hit with moderate exit velocities, around 85 mph, and significant backspin, up to 1200 rpm, which imparts a towering arc rather than forward distance.^[33] Unlike general fly balls that reach the outfield, pop-ups remain confined to infield areas, making them distinct in classification.^[32] The descent of a pop-up features extended hang time, often lasting 5 to 7 seconds, due to the backspin generating a Magnus force that counters gravity and prolongs the ball's air time.^[33] This hang time can create visibility challenges, particularly in day games under high-sky conditions where the ball blends against the bright background, reducing contrast for fielders.^[33] Wind currents further complicate the trajectory, potentially causing loops or cusps near the apex, with landing distances varying from 30 to 130 feet depending on environmental factors and spin.^[33] Infield defense against pop-ups requires coordinated effort from multiple fielders who converge on the landing zone, emphasizing clear verbal communication to prevent collisions, such as calling "mine" or "I got it" to establish priority.^[34] Established priorities guide this process, with the shortstop typically having precedence over other infielders, followed by the second baseman, while the pitcher often yields to middle infielders on shallow pops.^[34] If the pop-up lands fair and is caught before touching the ground, it results in an automatic out for the batter.^[32] Strategically, pop-ups offer minimal offensive value, resulting in an out approximately 99% of the time, comparable to a strikeout but requiring contact, which underscores their inefficiency for advancing runners or scoring.^[35] They rarely occur intentionally, as batters aim to avoid such high-angle mishits that stem from poor swing mechanics or defensive shifts, instead favoring lower trajectories for hits.^[36] High pop-up rates among hitters often signal broader issues in plate discipline rather than a viable tactic.^[32]

Special Cases and Rules

Infield Fly Rule

The infield fly rule is a specific regulation in baseball designed to protect baserunners from unfair defensive strategies. It declares the batter automatically out on a fair fly ball—not including a line drive or attempted bunt—that an infielder can catch with ordinary effort, provided there are fewer than two outs and either runners on first and second base or the bases loaded.^[37] For this purpose, the pitcher, catcher, and any outfielder positioned in the infield are considered infielders.^[37] The rule applies to fly balls, such as pop-ups, that remain in fair territory near the infield.^[37] Historically, the infield fly rule was introduced by the National League in 1895 to counteract a tactic where infielders intentionally allowed easy pop-ups to drop untouched, thereby forcing runners to advance and enabling easy double or triple plays by tagging the bases.^[38] This practice had become prevalent in the late 19th century, exploiting the force play mechanics to disadvantage offense.^[39] The rule's wording has evolved but retains its core intent in modern play, as codified in Major League Baseball's Official Rules under Definitions of Terms and Rule 5.09(a)(5).^[37] Upon determining the conditions are met, the umpire must immediately and loudly declare "Infield Fly" to alert players and spectators, while pointing toward the sky or fair territory as a visual signal; if the ball is near the baselines and may drift foul, the call is "Infield Fly, if fair."^[37]^[40] The ball remains live after the declaration, meaning the batter is out regardless of whether the ball is caught, but runners are no longer forced to advance and may attempt to advance at their own peril or tag up and run if the ball is caught.^[37] If the ball falls untouched and bounces foul before passing first or third base, it is treated as a foul ball; however, if it bounces fair before those bases, the infield fly ruling stands.^[37] The rule does not apply to line drives, attempted bunts, or ground balls, as these do not meet the criteria of a catchable fair fly ball with ordinary effort.^[37] Additionally, if an infielder intentionally drops the ball under infield fly conditions, the play continues live rather than resulting in a dead ball, prioritizing the rule's activation.^[37] The umpire's judgment on catchability is final and immediate, based on factors like the ball's trajectory and infielder positioning, without regard to field conditions such as grass or baselines.^[37]

Foul Tips

A foul tip occurs when a batter makes light contact with a pitched ball, causing it to travel sharply and directly from the bat to the catcher's glove or mitt, where it is legally caught without first touching the ground or any other object.^[41] This contact is typically glancing and produces a low-trajectory deflection, distinguishing it from a standard foul ball. Unlike a foul ball, which is ruled dead upon landing in foul territory and counts as a strike only if the batter has fewer than two strikes, a foul tip is not classified as a foul ball under the rules and always counts as a strike regardless of the number of prior strikes.^[41] It requires an unbroken, direct path to the catcher without any bounce or intermediate contact, ensuring the ball remains live after the catch.^[42] If the batter has fewer than two strikes, a caught foul tip simply advances the strike count, and play continues with runners able to advance at their own risk since the ball stays live.^[41] However, with two strikes, it constitutes the third strike, resulting in an out for the batter, though runners may still attempt to advance if the catcher fails to control the ball. Catchers rely on specialized protective gear, including a reinforced mitt, face mask, chest protector, and shin guards, to safely handle foul tips, which can travel at high speeds close to the plate.^[43] The face mask, invented in 1875 by Fred Thayer specifically to shield against foul tips, marked a pivotal advancement in catcher safety.^[44] The foul tip rule has evolved since the 1880s, when a 1880 change required catchers to catch the third strike—including foul tips—on the fly for an out, prompting the widespread adoption of backstops and protective equipment behind the plate.^[45] By 1896, the rule defined a foul tip more narrowly as a foul ball not rising above the batter's head and caught within ten feet of the plate.^[46] A significant 2020 update to the Official Baseball Rules simplified the definition by removing the requirement for contact with the catcher's hands or glove, allowing it to apply if the ball reaches any part of the catcher directly, provided it is caught.^[47]

Bunts

A bunt is an intentional batted ball in baseball where the batter does not swing fully but instead meets the pitch lightly with the bat to tap it slowly into the infield, typically in front of the plate or along the baselines, aiming for a base hit or to advance runners via sacrifice.^[48] This deliberate weak contact contrasts with full swings, prioritizing placement over power to exploit defensive positioning and create opportunities for baserunners. The primary purposes include the sacrifice bunt to advance a runner at the cost of an out, or offensive bunts like the drag or push to achieve a hit, especially for batters with speed.^[49] Effective bunting requires a square stance, where the batter pivots both feet toward the pitcher and holds the bat with the top hand near the knob and the bottom hand higher on the barrel for control.^[50] The batter deadens the ball by angling the bat downward at about 45 degrees while keeping it level through contact, absorbing the pitch's energy rather than propelling it, which directs the ball softly toward desired areas.^[51] Success hinges on precise bat control to avoid pop-ups or hard contact, as well as the batter's ability to read the pitch location and adjust the bat angle accordingly.^[52] Common types of bunts include the sacrifice bunt, where the batter intentionally gets out to move a runner from first to second or second to third; the drag bunt, executed by speedy left-handed batters who slide their right foot forward while directing the ball toward the right side for a hit; and the push bunt, used by right-handed batters to angle the ball to the left side opposite their stance.^[53] A foul bunt occurs when the batted ball lands in foul territory, counting as a foul ball and thus a strike against the batter, except on the third strike where it results in an out if caught by the catcher.^[54] Key success factors for bunts involve the batter's mastery of bat angle to deaden the ball effectively, minimizing bounce and distance, while fielders, particularly the pitcher and third baseman, charge aggressively to field and throw out the batter or runners.^[55] In high-leverage situations, such as with a runner on third and fewer than two outs, a well-executed bunt can score a run by forcing defensive errors during the charge.^[48] The strategic use of bunts has declined in the analytics era since the 2010s, as data shows they often yield lower expected run values compared to swinging for hits, especially with the universal designated hitter reducing weak-hitting pitchers' bunting opportunities.^[56] Modern analysis emphasizes that in most countable situations, putting the ball in play with a full swing produces better outcomes than the guaranteed out of a sacrifice bunt.^[57]

Statistical Analysis

Basic Metrics

Basic metrics for batted balls provide foundational ways to quantify and categorize the outcomes of balls put into play by batters, excluding home runs, walks, and strikeouts. These metrics primarily focus on the trajectory and type of contact, expressed as percentages of total batted ball events (BBE), which include all fair balls excluding bunts and home runs. The core classifications are ground balls (GB), fly balls (FB), line drives (LD), and pop-ups (PU), with percentages denoted as GB%, FB%, LD%, and PU% respectively. These rates sum to 100% for GB%, FB%, and LD%, while PU% is a subset of FB% representing infield flies.^[5] Tracking of these metrics relies on classifications made by official scorers during games, who determine basic outcomes like hits or outs based on trajectory and landing location, supplemented by video-based systems for aggregation. For instance, simple counts such as ground outs versus fly outs per game have been recorded since the early days of organized baseball, but detailed batted ball splits emerged in the 1980s through computerized data collection by firms like STATS Inc., enabling league-wide analysis. Comprehensive, standardized tracking began in 2002 via Baseball Info Solutions (BIS), which uses multiple observers to categorize each batted ball based on its path: ground balls bounce before reaching the outfield, line drives have a flat trajectory, fly balls arc high, and pop-ups are short infield flies.^[58]^[5] League-wide averages illustrate typical distributions, with 2025 MLB data showing 41.8% GB, 19.8% LD, 38.4% FB, and 9.7% PU (as a share of fly balls).^[59] These rates have trended slightly lower for ground balls in recent years, dropping to 41.8% in 2025 from 43.1% in 2015, reflecting shifts in hitting strategies. Ground balls tend to yield more singles due to their speed along the ground, while line drives produce a higher proportion of doubles and overall hits, and fly balls contribute disproportionately to extra-base hits like doubles when pulled.^[5]^[60] These basic metrics are essential for evaluating hitter tendencies, such as identifying "ground ball hitters" who exceed 50% GB% through low-launch-angle swings, often prioritizing contact over power, versus "fly ball hitters" with elevated FB% (above 40%) who aim for home runs but risk more outs. For example, contact-oriented players like Ichiro Suzuki historically posted GB% around 55%, boosting batting averages via infield singles, while power hitters like Aaron Judge maintain FB% over 45% to maximize slugging. Such profiles help assess a batter's skill in controlling contact type, informing scouting and fantasy evaluations without requiring advanced physics.^[5]^[61]

Advanced Analytics

Advanced analytics in baseball have revolutionized the evaluation of batted balls by leveraging sensor technology to capture granular data on their physical properties, enabling predictive modeling and deeper insights into offensive performance. Since the introduction of Statcast in 2015, metrics derived from high-speed cameras and radar systems have quantified aspects such as the speed, trajectory, and rotation of batted balls, shifting analysis from traditional outcomes to underlying mechanics. Key metrics include exit velocity, which measures the speed of the ball immediately after contact with the bat, with a league average of 89.4 mph across Major League Baseball (MLB) batted balls as of 2025.^[62] Launch angle, the vertical angle at which the ball leaves the bat, is another critical measure; angles between 10 and 30 degrees are optimal for producing hits, as they balance distance and the likelihood of evading fielders.^[21] Spin rate, particularly backspin, enhances carry distance by creating lift through the Magnus effect, allowing fly balls to travel farther than they would with neutral or topspin rotation.^[63]^[64] These metrics feed into basic expected value models that estimate outcomes based on physical inputs. For instance, expected weighted on-base average (xwOBA) is calculated as a function of exit velocity, launch angle, and sometimes sprint speed for ground balls, providing a probabilistic assessment of a batted ball's value independent of defensive positioning:

\text{xwOBA} = f(\text{exit velocity}, \text{launch angle}, \text{sprint speed})

where the function is derived from historical Statcast data since 2015 to predict weighted offensive contributions.^[65]^[13] Statcast's comprehensive dataset, encompassing over 700,000 batted ball events annually, underpins these models by correlating physical parameters with results like hits or outs. In applications, these analytics influence metrics such as batting average on balls in play (BABIP), where a batter's profile—favoring line drives with high exit velocities—can sustain higher BABIP rates compared to ground-ball heavy approaches.^[66] The hard-hit rate, defined as the percentage of batted balls with exit velocities exceeding 95 mph, serves as a proxy for consistent power, with elite hitters often exceeding 45% in this category to drive extra-base hits.^[13] The evolution of these tools traces back to the integration of PITCHf/x in 2008, which initially tracked pitches but laid groundwork for batted ball analysis by providing velocity and movement data.^[67] Statcast's 2015 rollout expanded this to full batted ball tracking, enabling granular breakdowns and predictive scouting models that forecast player potential based on launch angle tendencies and spin efficiency.^[68] For example, scouts now use simulated trajectories from these systems to identify prospects with optimal batted ball profiles before they reach the majors.^[69]

Safety Considerations

Risks to Players

Batted balls pose significant risks to players on the field, particularly through high-velocity line drives that can strike infielders and pitchers at speeds exceeding 100 mph, often resulting in fractures, concussions, or other severe injuries.^[70] Line drives to infielders, which travel in a nearly straight path close to the ground, leave limited reaction time—typically under 0.5 seconds—for defensive players to avoid impact, leading to common injuries such as broken bones in the legs, arms, or face. Pop-ups, while less lethal in speed, frequently cause collisions among outfielders or between infielders and pitchers pursuing the ball, resulting in head trauma, sprains, or dislocations due to miscommunication or overlapping pursuit paths.^[71]^[72] In Major League Baseball (MLB), batted ball-related injuries occur several dozen times per season, with pitchers alone accounting for approximately 175 documented instances of being struck in 2024, consistent with recent seasons, many leading to time on the injured list for contusions, fractures, or concussions.^[73] Annually, these injuries contribute to approximately 15-25 significant cases across players, with pitchers experiencing 10-18 high-grade impacts (e.g., 10+ days missed) per season in recent years like 2023 (18 cases).^[74] Protective measures have evolved to mitigate these hazards, with batting helmets becoming mandatory in MLB since 1958 to shield hitters from errant pitches, though fielders rely primarily on positioning and gloves. Efforts to test softer baseballs with reduced compression have been explored by the U.S. Consumer Product Safety Commission (CPSC), demonstrating that such balls can lower injury severity by absorbing impact energy, particularly in youth and amateur play, with potential applications to professional levels. Training programs emphasize reaction time drills, such as response simulations to batted balls, which studies show can improve fielders' decision-making speed by up to 20% through repeated exposure to variable trajectories.^[75]^[76]^[72] Positional vulnerabilities highlight pitchers as the most endangered group, facing comebackers directly from their mound position and comprising over 60% of overall MLB injuries, with batted balls contributing significantly to head and lower-body trauma in this role. Infielders, especially shortstops and third basemen, follow closely due to their proximity to the batter, where line drives often target the legs or torso, exacerbating risks during high-stakes defensive plays.^[77]^[78]

Hazards to Spectators

Spectators at baseball games face significant risks from batted balls, primarily foul balls and home run line drives that enter the stands, with an estimated 1,750 injuries occurring annually across major and minor league games in the United States.^[79] These incidents often involve high-velocity balls traveling over 100 miles per hour, striking fans in unprotected seating areas and causing concussions, fractures, and in rare cases, fatalities.^[80] On average, more than 50 foul balls are hit per Major League Baseball (MLB) game, with approximately 73% of them landing in spectator areas, creating thousands of potential exposures per season.^[81]^[82] Notable events underscore the severity of these hazards, such as the 2017 incident at Yankee Stadium where a young girl was struck in the face by a 105-mile-per-hour foul ball, resulting in a life-threatening skull fracture and brain injury that required multiple surgeries.^[83] In 2018, a Dodgers fan, Linda Goldbloom, died from blunt force trauma after being hit in the head by a foul ball during a game against the San Diego Padres, marking one of the rare but tragic fatalities in recent MLB history.^[84] These cases, along with over 800 documented injuries from 2012 to 2019, highlight how even brief distractions can lead to irreversible harm in seats close to the field.^[80] To mitigate these risks, MLB has implemented safety protocols including verbal warnings broadcast during games, usher guidance to direct fans to safer seating, and expanded protective netting.^[85] In December 2015, following analytics on foul ball trajectories that revealed high danger zones near the dugouts, MLB recommended extending netting from behind home plate to at least the ends of the dugouts, a measure adopted voluntarily by several teams initially.^[86] By the 2020 season, MLB mandated that all 30 teams extend protective netting from behind home plate to at least the ends of the dugouts, with many extending further down the foul lines, significantly reducing exposures in the most vulnerable areas behind home plate. Since 2020, several teams have voluntarily extended netting to the foul poles, amid continued advocacy for comprehensive coverage, as noted in a 2025 report estimating thousands of annual exposures.^[87]^[88] Legally, the "Baseball Rule" has historically limited stadium operators' liability for spectator injuries from foul balls, establishing that fans assume the inherent risk of such incidents by attending games, provided basic protections like initial netting are in place.^[89] This doctrine, originating from early 20th-century court cases, shields teams from lawsuits unless negligence—such as failing to maintain required netting—is proven.^[89] However, high-profile injuries since 2015, coupled with trajectory studies showing that 75% of foul balls into stands travel below 50 feet high, have fueled advocacy for full foul-pole-to-foul-pole netting to override these limitations and enhance overall spectator safety.^[90]

References

[1]
https://www.baseball-almanac.com/dictionary-term.php?term=batted%20ball
[2]
Fair Ball | Glossary | MLB.com
### Summary of Fair Ball Definition and Relation to Batted Ball
[3]
Foul Ball | Glossary - MLB.com
Any batted ball that first contacts a fielder while the ball is in foul territory is considered foul. If not touched by a fielder in fair territory, any batted ...
[4]
Batted Ball Event (BBE) | Glossary - MLB.com
A Batted Ball Event represents any batted ball that produces a result. This includes outs, hits and errors. Any fair ball is a Batted Ball Event.
[5]
GB%, LD%, FB% - Sabermetrics Library - FanGraphs
Feb 17, 2010 · Batted ball statistics are fairly straightforward: they express the share of a batter's balls in play are line drives, ground balls, or fly balls.
[6]
[PDF] OFFICIAL BASEBALL RULES
This code of rules governs the playing of baseball games by professional teams of Major League Baseball and any league within the professional.
[7]
Catcher Interference | Glossary - MLB.com
The batter is awarded first base if the catcher (or any other fielder) interferes with him at any point during a pitch.
[8]
The Rules: Advancing on Foul and Fair Batted Balls
"No ace or base can be made on a foul strike." This rule referenced a foul batted ball. The term "foul strike" was not used again until 1869 by the National ...
[9]
[PDF] OFFICIAL BASEBALL RULES
A FLY BALL is a batted ball that goes high in the air in flight. A ... the Official Baseball Rules (e.g., Definitions of Terms, Infield. Fly), is an ...
[10]
Expanded replay approved, to begin this season - MLB.com
Jan 16, 2014 · ... instant replay was unanimously approved at the quarterly Owners ... calls, plays at first base, force plays, tag plays, fair-foul and ...<|separator|>
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Hit Probability as a Function of Foul-Ball Accumulation - SABR.org
There are two such “indicator” states that arise with foul balls. The first is when fouls account for the first two strikes—known as the “inside-the-count” (ITC) ...
[12]
Fly-ball Rate (FB%) | Glossary - MLB.com
Fly-ball rate is the percentage of balls hit into the field of play that are fly balls, which are flys to the outfield.<|separator|>
[13]
Statcast Exit Velocity & Launch Angle Breakdown - Baseball Savant
For a batter, EV50 is an average of the hardest 50% of his batted balls. For a pitcher it is the average of his softest 50% of batted balls allowed. Adjusted ...
[14]
Launch Angle in Baseball and Softball - The Hitting Vault
Launch angle is the vertical angle at which the ball leaves the bat. Ground balls are under 10 degrees, line drives 10-25, fly balls 25-50, and pop ups over 50.
[15]
Fly Ball Exit Velocity Breakdown - by Jon A - MLB Data Warehouse
Dec 22, 2023 · The average average (yes, I said average average) fly ball exit velo in that group is 94.95 miles per hour. The average average fly ball exit ...
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All Fly Balls Are Not Created Equal | The Hardball Times
Feb 6, 2014 · All batted balls (in the air for at least 1.5 seconds); Batted balls in the air between 2.5 and 4.0 seconds. If a ball is in the air 2.5 to 4.0 ...
[17]
Outfield 2: Tracking Fly Balls - Pro Baseball Insider
Pro baseball players offer free tips for outfielders tracking fly balls - choosing the best route, running efficiently, and positioning for a good throw.
[18]
Sacrifice Fly (SF) | Glossary - MLB.com
A sacrifice fly occurs when a batter hits a fly-ball out to the outfield or foul territory that allows a runner to score.
[19]
The Rise and Fall of the Deadball Era
Batter only retired on foul balls caught before hitting ground. 1894-1900: Foul bunts counted as strikes; 1901-1902: Other foul balls counted as strikes unless ...
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Offensive Explosion: Trends in Hitting Production in Major League ...
This led to three rule changes before the 1920 season that aimed to increase offensive production in order to balance out the dominance of “dead ball” pitching ...Missing: evolution | Show results with:evolution
[21]
Launch Angle (LA) | Glossary - MLB.com
Definition ; Ground ball: Lower than 10 degrees ; Line drive: 10-25 degrees ; Fly ball: 25-50 degrees ; Pop up: Higher than 50 degrees.
[22]
Where the Ground Ball Begins... - Beacon Athletics at Ballfields.com
Mar 2, 2017 · Hard dirt will lead to increased acceleration of the baseball and produce greater topspin. Soft dirt will mean deceleration of the ball and reduced topspin.Missing: average bounce grass
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Managing infield ball speed
Mar 15, 2016 · The goal with the pace of the ground ball is for it to be consistent from turf to dirt. This is especially important for middle infielders and their mental “ ...
[24]
Baseball Positions by Number
So, as an example, a 6 4 3 double play means the shortstop fielded the ball and threw it to the second baseman, who turned the double play by throwing it to ...
[25]
Exploring the Shift Dynamic | The Hardball Times - FanGraphs
Jun 20, 2014 · In most shifts, teams are betting that the extra value added by converting more ground balls and line drives into outs, outweighs the (sometimes ...
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Are Groundball Pitchers Overrated? - The Hardball Times - FanGraphs
Feb 20, 2015 · Ground balls turn into hits only about 23 percent of the time, and almost never go for extra bases, for an average wOBA of .213. To put that ...
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GB%, LD%, FB% - Sabermetrics Library - FanGraphs
Feb 17, 2010 · In other words, a pitcher with a 55% ground ball rate will have a lower BABIP on grounders than a pitcher with a 45% ground ball rate.
[28]
Line drive - BR Bullpen - Baseball-Reference.com
Oct 29, 2009 · A line drive is a batted ball hit in a relatively straight line. It is distinguished from a fly ball, which is hit with a high arching trajectory, and a ground ...
[29]
Red-hot Sano living in the line-drive zone | MLB.com
Sep 2, 2015 · His average distance of 278.22 feet was first, just ahead of Ortiz. It's a simple process, really -- hitting the ball hard at an angle where ...
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The Physics of Fielding - The Hardball Times - FanGraphs
Feb 18, 2015 · ... straight line distance from his initial ... As the launch angle increases, the trajectory changes from a line drive to a lazy fly ball.
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Checking the Numbers: Much Ado About Liners | Baseball Prospectus
Jun 25, 2009 · In terms of exact figures, the liner/hit conversion rate averages out to 73 percent, roughly three times as often as balls beaten into the ...
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Pop-up Rate (PO%) | Glossary - MLB.com
Pop-up Rate (PO%). Definition. Pop-up rate represents the percentage of balls hit into the field of play that are characterized as pop-ups.Missing: characteristics defense<|control11|><|separator|>
[33]
[PDF] Paradoxical pop-ups: Why are they difficult to catch?
Players describe these batted balls as “tricky” or “deceptive,” and at times they are seen lunging for the ball at the last instant of the ball's descent. “Pop- ...
[34]
Baseball Pop Fly Priorities
Centerfielder has priority over the left and right fielders. Outfielders have priority over the infielders. Shortstop has priority over everyone in the infield.
[35]
Offensive Batted Ball Statistics and Their Optimal Uses
Aug 11, 2015 · Not for BABIP. And typically, weak or medium contact results in ground balls, and those have a higher BABIP. But ground balls can be hit hard ...
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We Have a Pop-Up Controversy | FanGraphs Baseball
Sep 26, 2016 · Think about what you know about hitters and pop-ups. Pop-ups, for all hitters, are bad. They might as well be one-pitch strikeouts.
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2025-official-baseball-rules.pdf
No information is available for this page. · Learn why
[38]
The Infield Fly Rule: A History and Explanation - MLB.com
May 13, 2019 · Explaining the infield fly rule · There must be runners on first and second base, or the bases must be loaded (runners on first, second, and ...
[39]
Revisiting the Origin of the Infield Fly Rule
Nov 27, 2018 · The 1897 rules codified this practice, mandating that the umpire “shall, as soon as the ball is hit, declare an infield or an outfield hit,” ...
[40]
Umpire Signs & Signals - UmpireBible
Oct 16, 2023 · Infield Fly. When you're in an infield fly situation, signal by touching the brim of the hat. Some crews indicate the number of outs by ...
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Foul Tip | Glossary - MLB.com
Should the batter produce a foul tip after previously accruing two strikes, the foul tip is considered strike three and the batter is out. The term "foul tip" ...
[42]
Foul Ball / Foul Tip - UmpireBible
Mar 21, 2023 · When a tipped batted ball is caught by the catcher after the ball hits his mask (for example), his chest, or anything else, this IS a foul tip ( ...
[43]
The Evolution of Catcher's Equipment
Early catchers had no protection, then a rubber mouth protector, then a mask, and finally a full suit of armor. Early masks were called "rat traps".
[44]
Baseball Advertising Trade Cards 3rd edition Catching Equipment
The catcher's face mask was invented in 1875 by Fred Thayer to protect catchers against vicious foul tips. It was first used in the same year by James Tyng of ...
[45]
Encyclopedia of Baseball Catcher's Equipment - History
Backstops began crowding the plate in 1880 when a rules change dictated that the final strike, including foul tips, had to be caught on a fly for a putout.
[46]
Foul tip caught by catcher - Ask the Umpire
May 1, 2025 · The rules of 1896 defined a foul tip as a foul ball that does not rise above the batsman's head and is caught by the catcher within ten feet of ...Foul Tip: Rule Change 2020 OBR - Professional - Umpire-EmpireFoul Tip vs. Foul "Trap" - Situations - Umpire-EmpireMore results from umpire-empire.comMissing: history | Show results with:history<|control11|><|separator|>
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[PDF] Summary of Baseball Rules Changes - Retrosheet
” In 2020, the definition was changed to, “A foul tip is a batted ball that goes sharp and direct from the bat to the catcher and is legally caught.” The ...
[48]
Bunt - BR Bullpen - Baseball-Reference.com
Jun 2, 2024 · A bunt is a batted ball not swung at, but intentionally met with the bat and tapped slowly within the infield.Missing: techniques | Show results with:techniques
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Sacrifice hit - BR Bullpen - Baseball-Reference.com
Jun 27, 2020 · A sacrifice hit (also known as a sacrifice bunt, and abbreviated SH) is credited to a batter who successfully advances one or more runners by bunting the ball ...Missing: techniques strategy
[50]
[PDF] FUNDAMENTALS - Sacrifice Bunt - Ngin
Bat Angle: Pre-setting the bat angle toward first or third base will eliminate unnecessary bat movement when the pitch is in flight. Ideally, bunt toward first.
[51]
Fundamentals of Bunting - Gary Varsho Baseball
Good bunting requires a specific stance, barrel control, bat angle, and direction towards 1st or 3rd base, not just a perfect bunt.
[52]
Baseball Bunt Guide: Learn How to Bunt in Baseball
Mar 15, 2022 · Here, we'll explore the correct way to bunt, the various types of bunts, the right situation to bunt and the rules for bunting.Missing: push technique
[53]
Types of Bunts in Baseball - CoachUp Nation
Here are the different kinds of bunts you can perform in a bunting situation: Sacrifice Bunt, This is the most common bunt.Missing: foul technique strategy decline analytics
[54]
Why are baseball's foul ball rules so weird? - MLB.com
May 10, 2019 · “A FOUL BALL is a batted ball that settles on foul territory ... Back in the early days of baseball in the 19th century … well, there ...
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Every Bunt of the 2023 Postseason, Ranked - FanGraphs Baseball
all 26 of them — for procedural and results-based value, tactical and ...Missing: definition | Show results with:definition
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A Time to Slug, and a Time to Bunt | FanGraphs Baseball
Sep 5, 2023 · Bunts are on the decline in this age of universal DH and empirical rigor, but those who choose to bunt can prosper.Missing: analytics | Show results with:analytics
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Strikeouts: Definitely Bad, Likely Necessary | The Hardball Times
Apr 18, 2014 · An analysis of the relationships between strikeouts and total offensive contributions, delving into sources of cause and effect.Missing: analytics | Show results with:analytics
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Baseball Therapy: The Fly Ball ... Revolution?
Jun 14, 2017 · Going back that far, we do not have launch-angle data, but we do have data on the types of batted balls that were struck (i.e., fly ball, ground ...<|separator|>
[59]
Groundball Rates Are Dropping — And Hitters Aren't the Only Ones ...
Aug 8, 2025 · According to Statcast, from 2015 to 2025, the league-wide groundball rate has dropped from 47% to 42.3%. In other words, 10% of all groundballs ...
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Beginner's Guide to Sabermetrics: LD%, GB%, FB% - FantasyPros
May 28, 2015 · Line Drive = 20% Ground Ball = 45% Fly Ball = 35%. Because regular counting stats (HR, RBI, extra base hits, etc.) don't tell the whole story ...
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Statcast Leaderboard | baseballsavant.com - MLB.com
Rk. For a batter, EV50 is an average of the hardest 50% of his batted balls. For a pitcher it is the average of his softest 50% of batted balls allowed.Exit Velocity & Barrels · Top Performers · Statcast Metrics Context · Fielder - All
[62]
More Fun With Batted Ball Spin Data | FanGraphs Baseball
May 26, 2022 · “The increased lift with backspin (which increases distance) gets overwhelmed by the increased drag (which decreases distance) once the spin ...
[63]
Understanding Rapsodo Hitting Data: Spin Rate
Jul 4, 2022 · Spin rate on batted balls is very similar to spin rate in pitching: backspin will keep the ball in the air longer, much like how a high spin ...
[64]
Expected Weighted On-base Average (xwOBA) | Glossary - MLB.com
Expected Weighted On-base Average (xwOBA) is formulated using exit velocity, launch angle and, on certain types of batted balls, Sprint Speed.
[65]
A New BABIP for a Statcast Era | RotoGraphs Fantasy Baseball
May 16, 2016 · Using Statcast data, we can build a more granular view of batted balls, and define new types of batted balls, along with their observed ...
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Pitch-tracking Era | Glossary - MLB.com
The pitch-tracking era covers 2008 to the present -- the time period for which pitch type and pitch velocity data is available for Major League games.
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What is PITCHF/x? - Sabermetrics Library - FanGraphs
Feb 17, 2010 · PITCHf/x is a pitch tracking system, created by Sportvision, and is installed in every MLB stadium since around 2006.Missing: date | Show results with:date
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Using Statcast Data to Predict Hits | The Hardball Times - FanGraphs
Jun 14, 2016 · Using a random forest algorithm to classify batted balls into different outcomes based on elements of Statcast data.<|control11|><|separator|>
[69]
Giancarlo Stanton's 120 mph single | 07/31/2024 - MLB.com
Jul 31, 2024 · Statcast measures the exit velocity and bat speed of Giancarlo Stanton's 120 mph single with a bat speed of 86.4 mph.Missing: line drive
[70]
Summer Pitch: How to Prevent Baseball Injuries This Season
Jul 21, 2025 · Clear communication is key to preventing on-field collisions. Encourage players to loudly call for pop-ups and fly balls so they don't crash ...
[71]
[PDF] Response time to batted balls - The Research Repository @ WVU
The book also reported that from age 20 to 60 there is about a 20% reduction in reaction time. In baseball, reaction time is influenced by the height of ...
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Reese Olson The Latest In Run Of Pitchers Hit By Batted Balls
May 21, 2024 · Entering Monday, there were 53 total instances of a pitcher being hit by a batted ball and receiving some type of injury grade. Using 'on pace ...
[73]
Killed by Pitched Ball: Finding Ray Chapman on Chronicling America
Aug 2, 2013 · The sound of the ball coming off Chapmans head was so loud that Mays thought the ball had hit Chapmans bat, prompting him to field the ball and ...
[74]
Stat of the Week: Pitcher Injuries On Comebackers On The Rise
May 18, 2023 · There have been 10 instances of a pitcher being hit by a ground ball or line drive this season and receiving a 4 or 5 injury grade from our ...Missing: annual | Show results with:annual
[75]
3.08 Helmets - Baseball Rules Academy
Protective Equipment SECTION 15. a. Batter's Helmet. It is required that every player wear a double earflap protective helmet while batting, on deck and running ...
[76]
CPSC Releases Study of Protective Equipment for Baseball
Based on its analyses, CPSC found that three pieces of safety equipment will help reduce injuries. Softer-than-standard baseballs and softballs, which have a ...
[77]
Baseball Injuries Douglasville - Planet Chiropractic
... MLB, over 60% comes from pitchers. Most of this is in the form of shoulder and elbow injuries, not from impact-related baseball injuries as you might expect.<|control11|><|separator|>
[78]
Descriptive Epidemiology of Collegiate Men's Baseball Injuries - NIH
Pitchers received 13.9% (100/717) of their injuries from batted balls, with most (in terms of number and severity [10+ days' time loss]) occurring to the lower ...
[79]
Baseball Caught Looking as Fouls Injure 1,750 Fans a Year
Sep 9, 2014 · McHale declined to comment on Bloomberg's analysis and said Major League Baseball hasn't studied the frequency of foul ball injuries. MLB ...
[80]
Foul balls hurt hundreds of fans at MLB ballparks. See where your ...
Oct 1, 2019 · Data compiled for NBC News by the Elias Sports Bureau shows the number of foul balls per game has increased 10 percent since 2000. Even MLB ...
[81]
Exhibit A-1 — Foul Ball Safety Now!
MLB Estimates: On average, based on a 2019 report, there are 130,734 foul balls hit during an MLB regular season consisting of 2,430 games. That's more than 50 ...
[82]
Who is Liable for Injuries at a Baseball Game? - Dolan Law Firm
Aug 5, 2024 · According to a 2015 Boston Globe article, about 73% of foul balls end up in the stands. A lawsuit against the Red Sox in the 1990s revealed that ...
[83]
Young fan taken from Yankees game to hospital after being hit by ...
Sep 20, 2017 · A young fan at the Twins-Yankees game in New York on Wednesday was hit in the face by a foul ball and taken to a local hospital. The girl's ...
[84]
Husband of Dodgers fan fatally struck by foul ball - ABC News
Feb 6, 2019 · Husband of Dodgers fan fatally struck by foul ball: 'We didn't have time to react'. Linda Goldbloom died after attending a Padres-Dodgers game ...
[85]
MLB recommends netting between dugouts
After an in-depth study, Major League Baseball has recommended that all teams should lengthen the safety netting at their ballparks to increase fan safety.
[86]
Baseball Has a New Policy on Netting, but There's a Catch
Dec 18, 2015 · Under the new policy, teams are “encouraged” to extend the netting behind home plate a mere 70 feet or so down the foul lines, to the “near ends of both ...
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MLB to Expand Safety Netting at All 30 Stadiums for 2020 Season
Dec 11, 2019 · In an attempt to improve fan safety during games, all 30 Major League Baseball stadiums will have expanded netting next season.Missing: mandate | Show results with:mandate
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The Baseball Rule: Liability to Spectators for Foul Ball Injuries - NFHS
Nov 10, 2021 · A 2014 Bloomberg News report revealed that since the turn of the millennium, an average of 1,750 spectators per year were injured by foul balls ...
[89]
We Watched 906 Foul Balls To Find Out Where The Most ...
Jul 15, 2019 · Bloomberg News estimated in 2014 that 1,750 fans per year are hurt by batted balls at MLB games. Amid debates over how much protection teams ...<|separator|>