Major League Baseball is back. And the robots have arrived.
The defending World Series champion Los Angeles Dodgers opened Spring Training Thursday at Camelback Ranch in Glendale, Arizona, when they hosted the Chicago Cubs in the first MLB game (albeit an exhibition game) of 2025. The Dodgers got off to a slow start, falling to Cubs by a lopsided 12-4 score. But none of that was what made the game memorable. In fact, the Dodgers-Cubs spring matchup was certifiably historic.
Why? Because the game was the first ever in the Major Leagues to use a computerized system to call balls and strikes. Actually, the system, known as the Automated Ball-Strike system, or ABS, is not actually used to determine all balls and strikes. MLB will still use human umpires for that â at least for now.
Instead, ABS as it is currently utilized is a challenge system. A batter, pitcher or catcher may contest an umpire’s ball-strike call, and ask a computer using a pitch-location system known as Hawk-Eye to decide whether the ump’s call was correct.
Robot Umps Used in Minor Leagues Since 2019
ABS was first tested in an independent minor league in 2019, and then at eight ballparks in the Single-A Florida State League in 2021. Starting in 2023, every park at the Triple-A level was equipped with the technology to make the ABS system work.
Initially, ABS was used to make every call, taking human umps out of the picture, in some Triple-A games, and as a challenge-only system in others. But by June of 2024, MLB decided to keep ABS in place only for ball-strike challenges.
In 2025, the technology has been installed in 13 spring training parks, covering 19 of the 30 MLB teams (some teams share spring training facilities). That means every team will play at least one game in which players will be allowed to test the challenge system.
In Thursday’s Cubs-Dodgers game, it didn’t take long for players to call on the robot ump to do its thing.
“The historic moment, if you want to call it that, occurred in the bottom of the first inning when (Cubs pitcher Cody) Poteet faced (Dodgers hitter Max) Muncy,” recounted Bob Nightengale of USA Today. “He threw a 95-mph fastball that clipped the bottom of the zone on an 0-1 pitch, but it was called a ball. Poteet was convinced it was a strike and immediately challenged. The pitch was shown on the scoreboard, and in a matter of seconds, the call was immediately overturned.”
First MLB ‘Robot Ump’ Game Goes Off Without a Hitch
It’s that simple. Each team receives two challenges to start the game. To challenge a call, the pitcher, batter, or catcher must tap his head immediately after the pitch is called by the home plate ump. Managers, coaches and other players are not allowed to participate, and there is no waiting for a video analyst to determine whether to issue a challenge.
Only one other challenge was used in Thursday’s game, and the system was reported to work without a hitch.
âEverything worked well on Day One,” MLB executive vice-president Morgan Sword, who was on hand to observe the system’s debut, told Nightengale. âA good first step.”
The system will not be used in 2025 regular season games as MLB executives continue to evaluate its effectiveness. Based on minor league results, however, ABS does not cause games to slow down in any meaningful way. At the minor league level, ABS games were only 17 seconds longer, on average, than games that did not use the computerized challenge system.
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