Major League Baseball debuted an automated ball-strike (ABS) challenge system during 2024 spring training games, allowing teams to contest umpire calls on balls and strikes.[1] The system represents the first on-field use of challenge technology for pitch location calls in MLB-affiliated games.

Each team receives two challenges per game, which must be signaled by the catcher to the dugout within 10 seconds of the pitch. The home-plate umpire's call is reviewed against the ABS computer determination. A correct challenge overturns the call and retains the challenge for the team; an incorrect challenge results in forfeiture of one challenge.[1]

The ABS technology generates a batter-specific strike zone based on the average height of batters at the 50th percentile for their handedness and league. It builds on prior testing in Triple-A leagues during the 2023 season and the Arizona Fall League.[1][2]

The experiment follows the 2023 introduction of the pitch clock, larger bases and pickoff limits, which reduced average nine-inning game times to 2 hours and 36 minutes from 3 hours and 6 minutes in 2022. MLB attendance rose to 70,835,430 in 2023, up 9.6 percent from 64.5 million in 2022.[3]

MLB Commissioner Rob Manfred stated in March 2024 that the ABS challenge system was "on track" for potential implementation in regular-season games as early as 2025.[4]

Sources

1. MLB.com
   MLB to test PitchCom, automated ball-strike challenge system during 2024 Spring Training
   February 8, 2024
   https://www.mlb.com/news/mlb-to-test-automated-ball-strike-system-in-spring-training-2024
2. Mlb.com
   Automated ball-strike system to be tested in Triple-A in 2023
   May 5, 2023
   https://www.mlb.com/news/automated-ball-strike-system-triple-a-testing-in-2023
3. MLB.com
   MLB attendance increases in 2023
   October 1, 2023
   https://www.mlb.com/news/mlb-attendance-increases-in-2023
4. ESPN.com
   MLB's Rob Manfred: ABS challenge system on track for possible use in 2025
   March 25, 2024
   https://www.espn.com/mlb/story/_/id/39824845/mlb-rob-manfred-automated-strikes-abs-robot-umpires-2025