Xavier Savard, MJLST Staffer
First shown regularly on Major League Baseball (“MLB”) broadcasts in 1997, the glowing strike zone allowed television viewers to see what umpires missed.[1] Despite technological reforms to umpiring, the most fundamental calls in professional baseball, balls and strikes, have been left entirely to human judgment since 1869.[2] In September 2025, the MLB announced the rollout of the Automated Ball-Strike System (“ABS”), allowing teams to challenge pitches that the system will then review.[3] However, this challenge-based model represents solely a transitional step towards full automation. Due to pressures surrounding legalized sports betting, fairness, and broader advances intechnological developments, a fully automated system is increasingly likely in the future, despite concerns regarding collective bargaining and player pushbacks.
Diligently tested by the MLB since 2022, ABS is a high-speed camera system that locates the ball in relation to an individualized batter’s box and translates the location data over a private network, allowing a pitcher, catcher, or batter to challenge an umpire’s call.[4] Then, within fifteen seconds, the system reviews the pitch data and analyzes whether the ball passes within the tailored strike zone within fifteen seconds.[5] If the challenge is successful, the team retains its challenge; if not, the team loses it.[6] Teams start with two challenges.[7] According to the MLB’s 2024 Spring Training testing, players favor the challenge system because it retains the human element of the game.[8]
As a fan, I admit that I agree with the players. I like human umpires. The subjective element adds a certain unpredictability and excitement to the game, giving baseball its flair. While frustrating at times, this quality makes the game feel historic and connected to humanity. Yet, enjoying the human element does not change where baseball is heading.
The MLB has an implicit duty, derived from its Constitution and the Official Baseball Rules, to strive for fairness and accuracy in baseball.[9] This fiduciary-like duty is particularly evident in the “best interests of baseball” clause, which grants the MLB Commissioner broad authority to act in the interest of maintaining baseball’s integrity.[10] While this duty has historically been fulfilled through human umpires, the MLB’s tolerance of preventable errors that technology can reduce indisputably risks the integrity of the game.
The MLB has partnered with various sports betting organizations,[11] which raises its duty to employ a fairer and more accurate umpiring system. While there is some argument that the integrity of the game includes the presence of human umpires,[12] the MLB and its fans’ substantial financial entanglement with official partnership outweighs that argument. Now, accuracy is no longer just ideal but is a business requirement to preserve the reputation of the MLB and the fans’ expectations. When the MLB profits from wagers through official partnerships on games and fans risk significant sums of money, the tolerance for officiating errors should decrease. While umpires call roughly 93% of pitches correctly, the remaining 7% can drastically affect the game.[13] For example, in Game 4 of the 2025 NLDS matchup between the Dodgers and the Phillies, the umpire called a fourth ball on a clear strike, allowing a walk.[14] That batter eventually scored, and the pitcher’s team lost.[15] While it is difficult to know what would have happened had the pitch been called a strike, the truth is, we should not have to wonder. The pitch simply should have been called a strike in the first instance. Given how efficient and accurate the ABS is, the MLB should remove errors like these from the game through a full ABS.
These concerns are only magnified by the growth of sports betting is not going away anytime soon. Since the Supreme Court’s decision in Murphy v. NCAA in 2018, the sports betting industry has grown from $400 million in revenue in 2018 to $13.71 billion in revenue by 2024.[16] As the MLB continues to earn more revenue from its partnerships, the reliance on human umpiring compromises fairness and public trust in the game.
Additionally, while traditionalists argue that baseball is a game steeped in tradition, the game has always changed to increase fairness or to strengthen its commercial value. In 1935, the MLB had its first-ever night game, powered by innovative lighting equipment to allow spectators to come to the game after work.[17] Decades later, baseball adopted instant replay in 2008, which it drastically expanded upon in 2014.[18] More recently, in 2023, the MLB implemented a pitch clock.[19] These examples show that baseball’s tradition does not actually stop it from implementing technology to promote fairness and marketability.
Yet, the challenge-based system is only a temporary solution because it only corrects a minority of errors, those that players deem valuable enough to challenge. In the past study, the players challenged about 2-3% of calls, with about half of the challenges being successful.[20] That means another 5.5% of incorrect calls remain. Put another way, the challenge-based system only corrects 20% of incorrect calls are corrected. Challenge-based ABS still simply does not ensure maximum accuracy, failing to satisfy the MLB’s fairness obligations when full ABS is available.
One major obstacle to full ABS is the Major League Baseball Umpire Association (“MLBUA”). While the 2019 and 2024 collective bargaining agreements indicate that the MLBUA has been pro-ABS to a certain extent,[21] the MLBUA is likely to oppose full-ABS. Even in a world with full ABS, umpires are still necessary to make certain calls around the bases. Due to union protections under the National Labor Relations Act (“NLRA”),[22] implementing a fully automated system could pose a significant hurdle for the MLB.
Second, a full ABS may face resistance from players because it changes some important aspects of the game for pitchers and catchers. There is some evidence that veteran pitchers get a wider strike zone that they have “earned,” and catchers spend years developing their pitch-framing abilities.[23] Full ABS would reduce the impact of these skills. Yet, all rule changes impact how players play baseball, and history shows that fairness-based rule changes often improve the game for the better. In 2021, for example, the MLB began enforcing Rules 3.01 and 6.02(c), which suspend pitchers for using sticky substances on their hands.[24] Because some players were getting an unfair advantage by the way they played the game, the MLB enforced the rule. Simply put, just because rule changes alter how players have historically done their job does not mean it is not good for the integrity of the game.
A full ABS implementation from the challenge system is entirely consistent with baseball’s long-standing technological evolutions that promote integrity and fairness. It is merely a continuation of that pattern, necessitated by legalized sports betting and immense financial interests at stake. Still, collective bargaining obligations and player pushbacks ensure the future transition will be difficult.
Notes
[1] How Accurate is the Baseball Strike Zone Box on TV, Baseball Scouter, https://baseballscouter.com/baseball-strike-zone-on-tv/ (last visited Sept. 29, 2025).
[2] History.Com Editors, National League of Baseball is Founded, History (last updated May 25, 2025), https://www.history.com/this-day-in-history/February-2/national-league-of-baseball-is-founded.
[3] MLB Announces ABS Challenge System Coming to the Major Leagues Beginning in the 2026 Season, MLB (Sept. 23, 2025), https://www.mlb.com/press-release/press-release-mlb-announces-abs-challenge-system-coming-to-the-major-leagues-beginning-in-the-2026-season.
[4] Id.
[5] Id.
[6] Id.
[7] Id.
[8] Theo DeRosa, MLB Releases Spring Training ABS Challenge results, MLB (Mar. 26, 2025), https://www.mlb.com/news/automated-ball-strike-system-results-mlb-spring-training-2025?msockid=2b62cc077eaa61eb013dd8dc7f816092.
[9] See Major League Baseball Constitution, MLB (2000), https://sports-entertainment.brooklaw.edu/wp-content/uploads/2021/01/Major-League-Baseball-Constitution.pdf; Official Baseball Rules, MLB (2025), https://mktg.mlbstatic.com/mlb/official-information/2025-official-baseball-rules.pdf.
[10] Richard Justice, ‘Best Interests of Baseball’ a Wide-Ranging Power, MLB (Aug. 1, 2023), https://www.mlb.com/news/richard-justice-best-interests-of-baseball-a-wide-ranging-power-of-commissioner/c-55523182#:~:text=In%201921%2C%20the%20owners%20defined,exactly%20what%20it%20sounds%20like.
[11] Sam Carp, MLB Adds FanDuel as Third Sports Betting Partner, SportsPro (Aug. 16, 2019), https://www.sportspro.com/news/mlb-fanduel-sports-betting-sponsorship/.
[12] See Larry Gerlach, History of Umpiring, Steve O’s Umpire Res., https://www.stevetheump.com/umpiring_history.htm (last visited Oct. 9, 2025).
[13] Davy Andrews, Strike Three?! Let’s Check in on Umpire Accuracy, FANGRAPHS (Feb. 1, 2024), https://blogs.fangraphs.com/strike-three-lets-check-in-on-umpire-accuracy/.
[14] Zach Bachar, Phillies’ Sanchez Says Umpire Apologized for Crucial Missed Strike 3 Call vs. Dodgers, Bleacher Rep. (Oct. 10, 2025), https://bleacherreport.com/articles/25259222-phillies-sanchez-says-umpire-apologized-crucial-missed-strike-3-call-vs-dodgers.
[15] Id.
[16] Ehtan Mordekhai, The Aftermath of Murphy v. NCAA: State and Congressional Reactions to Leaving Sports Gambling Regulation to the States, CARDOZO J. ARTS & ENT. L.J. (Oct. 17, 2023), https://cardozoaelj.com/2023/10/17/the-aftermath-of-murphy-v-ncaa-state-and-congressional-reactions-to-leaving-sports-gambling-regulation-to-the-states/.
[17] Brian Murphy, 88 Years Ago, AL/NL Baseball Finally Saw the Light, MLB (May 23, 2024), https://www.mlb.com/news/first-night-game-in-al-nl-history.
[18] Instant Replay, BASEBALL REFERENCE, https://www.baseball-reference.com/bullpen/Instant_replay (last visited Sept. 29, 2025).
[19] Pitch Timer (2023 Rule Change), MLB, https://www.mlb.com/glossary/rules/pitch-timer?msockid=2b62cc077eaa61eb013dd8dc7f816092, (last visited Oct. 9, 2025).
[20] DeRosa, supra note viii.
[21] Dylan A. Chase, MLB, MLBUA Reach Tentative Labor Agreement, MLB Trade Rumors (Dec. 21, 2019), https://www.mlbtraderumors.com/2019/12/mlb-mlbua-reach-tentative-labor-agreement.html; Manny Randhawa, MLB Reaches New CBA Agreement with Umpires Association, MLB (Dec. 23, 2024), https://www.mlb.com/news/mlb-umpires-association-reach-collective-bargaining-agreement?msockid=2b62cc077eaa61eb013dd8dc7f816092.
[22] U.S. Dep’t Lab., What Are My Employees’ Rights Under the National Labor Relations Act (NLRA)?, https://beta.dol.gov/policy-governance/protections-rights/unions-collective-bargaining/employee-rights-nlra (last visited Oct. 9, 2025).
[23] Nayima Riyaz, “Change Is Always Tough” – MLB Veteran Voices Concern Over ABS System Amid Growing Popularity, Essentially Sports (Feb 26, 2025), https://www.essentiallysports.com/mlb-baseball-news-change-is-always-tough-mlb-veteran-voices-concern-over-abs-system-amid-growing-popularity/; Veteran Bias in MLB Umpiring: Hitters, Quantum Sports (Feb. 24, 2020), https://www.quantumsportssolutions.com/blogs/baseball/veteran-bias-in-mlb-umpiring-hitters.
[24] MLB Announces New Guidance to Crack Down Against Use of Foreign Substances, Effective June 21, MLB (June 15, 2021), https://www.mlb.com/press-release/press-release-mlb-new-guidance-against-use-of-foreign-substances?msockid=2b62cc077eaa61eb013dd8dc7f816092.