MLB announces ABS Challenge System coming to the Major Leagues beginning in the 2026 season
Major League Baseball (MLB) today announced that the Automated Ball Strike (ABS) Challenge System has been approved for Major League play by a vote of the Joint Competition Committee. Beginning in 2026, the “Challenge System” will be used in all Spring Training, Championship Season, and Postseason games. The Competition Committee – comprised of six owners, four active players and one active umpire – was created as part of the current Collective Bargaining Agreement negotiated between MLB and the Major League Baseball Players Association (MLBPA). MLB has extensively tested the use of ABS technology in Triple-A since 2022, in addition to testing during 2025 Major League Spring Training and the 2025 All-Star Game. The final design of the system, including moving to the ABS Challenge format, is a result of significant feedback from players, coaches, front office staff, umpires, and fans.
How It Works: The ABS Challenge System runs on a 5G private network from T-Mobile for Business’ Advanced Network Solutions. Twelve (12) Hawk-Eye cameras set up around the perimeter of the field track the location of each pitch. If a pitcher, catcher, or batter disagrees with the umpire’s initial call of ball or strike, he can request a challenge by immediately tapping on his hat or helmet and vocalizing a challenge. The pitch location is compared to the batter’s strike zone, and if any part of the ball touches any part of the strike zone, the pitch will be considered a strike. The home plate umpire will announce the challenge to the fans in the ballpark and a graphic showing the outcome of the challenge will be displayed on the scoreboard and broadcast. The entire process takes approximately 15 seconds.
ABS Challenge System Rules: Each club will start the game with two challenges, and all successful challenges are retained. Only the pitcher, catcher or batter may challenge an umpire’s call of ball or strike. Challenges must be requested immediately after the call, and players may not receive help from the coaching staff, other players, or anyone else. In each extra inning, a team will be awarded a challenge if it has none remaining entering the inning.
ABS Challenge System Strike Zone: The strike zone will be a two-dimensional rectangle that is set in the middle of home plate with the edges of the zone set to the width of home plate (17 inches) and the top and bottom adjusted based on each individual player’s height (53.5% of the batter’s height at the top and 27% at the bottom). As was the process ahead of 2025 Spring Training, independent testers will measure players in Major League Spring Training using a standardized process. MLB will certify each player’s official height before that player may appear in any Major League game.
Commissioner of Baseball Robert D. Manfred, Jr. said: “The previous rule changes that have been adopted by the Joint Competition Committee have had staying power and created momentum for the game. We used the same process with ABS that started with listening to fans, conducting extensive testing at the minor league level, and trying at every step to make the game better. Throughout this process we have worked on deploying the system in a way that’s acceptable to players. The strong preference from players for the Challenge format over using the technology to call every pitch was a key factor in determining the system we are announcing today. I commend the Joint Competition Committee for striking the right balance of preserving the integral role of the umpire in the game with the ability to correct a missed call in a high-leverage situation, all while preserving the pace and rhythm of the game. I thank the Major League Umpires for their collaboration and the Major League Players for their feedback in moving the game forward for the fans.”
John Stanton, Chairman of the Competition Committee and Chairman of the Seattle Mariners, said: “From its inception, the Joint Competition Committee’s constructive conversations between players, umpires and owners have produced rules that significantly improved the game for fans. The ABS Challenge System is another big step forward for the game. ABS Challenge strikes the right balance of putting a tool in the players’ hands to correct a missed call in a high leverage spot while retaining the human element of the game and adding a new fan-friendly engagement moment. I want to thank the Commissioner’s Office, the Players Association, and the Major League Umpires for their dedication to the greatest game ever invented.”
Minor League Baseball’s Florida State League (Single-A) has utilized ABS since 2021, Triple-A has had ABS in select parks since 2022, and ABS has been across all of Triple-A since 2023. ABS Challenge debuted at the Major League level in 2025 Spring Training. The 2025 All-Star Game in Atlanta also featured ABS Challenge.
ABS CHALLENGE Results – 2025 Spring Training
- Teams challenged just over four (4) pitches per game with a success rate near 50%, consistent with results observed during Minor League testing.
- The offense and defense challenged a similar number of pitches, but the defense was more successful (54% vs. 50% overturn rate).
- Catchers had the most success challenging (56% overturn rate for catchers vs. 50% for hitters and 41% for pitchers).