The controversial Automated Ball-Strike (ABS) challenge system is an unspoken contract between the only three people on the field who matter in the moment: the pitcher, catcher, and batter.
Baseball is a pastime laced with tradition, but it can also be an ambiguous sport. Did a pitcher throw strike three, or did it just miss the corner of the zone? So far, that decision has hinged on the umpire behind the plate. To improve this murkiness, Major League Baseball (MLB) is testing automated systems for calling balls and strikes—first in the minor leagues, then major league spring training, and most recently during the 2025 All-Star Game, powered by T-Mobile 5G tech.
Although the league could let computers determine every pitch, it’s not going down that path yet. Instead, it’s using a hybrid Automated Ball-Strike (ABS) challenge system, which lets certain players request a review of the computer’s verdict. And despite being a technology journalist, enthusiastic about screens and gadgets, I think the human-computer mix is the right choice.How the ABS Challenge System Works
With ABS, both teams get two challenges. The pitcher, catcher, and batter are the only ones who can invoke it immediately after a call. An advanced camera system checks each pitch. If one is challenged, then its precise location on the strike zone is shown to viewers, confirming or overturning the call. If a player is wrong, their team loses a challenge. If they’re right, they retain it.
„The call of a pitch impacts teams not just during the game, but also for future games because there are so many pitching decisions that have to be made as a result of pitch counts going up“, says Randy Wilkins, filmmaker and director of ESPN’s Derek Jeter docuseries The Captain.
