Something to look forward to: Tennis, cricket, and other sports have long used high-speed Hawk-Eye cameras to assist human officials. Major League Baseball has been testing its version of the technology for the past few years. Although previous trials have gone smoothly, it remains unclear whether players, umpires, and fans will accept the new rules.
MLB will use computerized high-speed cameras to call balls and strikes during Tuesday’s All-Star Game in Atlanta, marking another step toward automated officiating. The league has been testing the system in minor league and spring training games since 2019, with plans for regular season use beginning next year.
The Automated Ball-Strike System (ABS) uses several Hawk-Eye pose-tracking cameras to determine whether a pitch passes through the strike zone over home plate. Batters, umpires, and pitchers can challenge a call by tapping their head or helmet within two seconds. Each team is allowed two unsuccessful challenges per game, with no limit on successful ones.
However, ABS defines the strike zone differently from human umpires and the MLB rulebook, which could spark controversy. The league defines the zone as a cube extending the depth and width of home plate and the vertical distance between the middle of a batter’s torso and just below his knees. Furthermore, Arthur Daemmrich and Eric S. Hintz write that umpires often but not always call strikes when balls cross a rear corner of home plate.
In contrast, ABS measures the strike zone as a two-dimensional rectangle bisecting the width of the middle of home plate and extending between 53.5% and 27% of the batter’s height. Each player’s height is measured without cleats shortly before their first game, a process that takes less than a minute.
As in other sports, differences might arise between league regulations, an umpire’s view of the ball, and data from the cameras. Daemmrich and Hintz also suggest that changes in a player’s cleats or batting stance could offset ABS.
Also read: The Machines Calling Balls and Strikes – Baseball Joins the Tech Takeover
The AP reports that slightly over half of all challenges were successful during testing. Batters won exactly half of their challenges, the defense 54%, catchers 56%, and pitchers 41%.
Still, accuracy may not be the only factor that matters. Fans could become the ultimate arbiters, especially if ABS affects the competitiveness of the game. Iconic, game-changing calls from historic matches might not have occurred under the new system.
The All-Star Game at Truist Park in Atlanta begins at 8 p.m. Eastern Time on Tuesday, July 15. MLB’s Joint Competition Committee will decide later this summer whether to implement ABS in regular season games starting in 2026.