CLEVELAND, Ohio — Major League Baseball will introduce an Automated Ball-Strike Challenge System beginning in the 2026 season, allowing players to contest umpire calls on balls and strikes for the first time in the sport’s history.
The league’s joint competition committee approved the technology following extensive testing in minor league baseball and during 2025 spring training. The system will be used in all spring training games, regular season contests, and postseason play starting in 2026.
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Players can challenge an umpire’s ball or strike call by immediately tapping their hat or helmet and vocalizing the challenge. Twelve Hawk-Eye cameras positioned around the field will determine whether any part of the ball touched the strike zone, with the entire review process taking approximately 15 seconds.
“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,” Commissioner Rob Manfred said.
“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.”
Each team will begin games with two challenges and retain any successful challenges throughout the contest. Only pitchers, catchers, and batters may request challenges, and they cannot receive assistance from coaches or teammates. Teams receive an additional challenge in extra innings if they have none remaining.
The strike zone will be a two-dimensional rectangle spanning home plate’s 17-inch width, with height adjusted for each batter based on standardized measurements taken during spring training.
During 2025 spring training testing across 288 games, teams averaged 4.1 challenges per game with a 52.2% success rate. Defensive players were slightly more successful than offensive players, with catchers achieving the highest overturn rate at 56%.
John Stanton, competition committee chairman and Seattle Mariners chairman, said the system “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.”
Fan reaction during spring training was largely positive, with 52% reporting a very positive impact and 20% citing a slightly positive effect on their game experience. Only 10% of fans surveyed reported negative reactions to the technology.
MLB has tested automated ball-strike technology in Triple-A since 2022 and in Single-A via the Florida State League since 2021. The challenge format debuted at the major league level during 2025 spring training and was featured in the All-Star Game in Atlanta.