MLB Using Robot Umpires: What To Know About ABS Challenge System

Major League Baseball has introduced several new rules in recent seasons, but perhaps the most significant one is being tested during Spring Training this year.

After experimenting with the Automatic Ball-Strike (ABS) challenge system across the Minor Leagues, MLB has brought the new technology to select Cactus League and Grapefruit League games.

The Los Angeles Dodgers got their first look of the system in their 2025 Spring Training opener against the Chicago Cubs when Cody Poteet challenged his 0-1 pitch to Max Muncy.

The original call of a ball was overturned by ABS and the count became 1-1 rather than 2-0.

“It’s interesting. I don’t hate the idea of it,” Muncy said of the ABS challenge system.

“The technology, I think they’ll admit, is not entirely there yet, but it’s a cool idea. I like it. It’s cool, something that’s different.

“When that ball crossed, I thought it was a strike right away. I looked out there and he’s tapping his head, I’m like, ‘Well, I’m going to be the first one.’ I knew it was a strike. The idea of it is cool and it’s definitely interesting, but we’ll see how it progresses.”

Dodgers manager Dave Roberts was unsure how he would take to the challenge system, but believes it is a positive to the game.

“It was good,” Roberts said of his first impression.

“I think it’s actually a pretty good system. Obviously, trying to figure out how many challenges makes the most sense in a big league ballgame. I like it, because especially in a big spot, you want to get the call right.”

How does MLB automatic ball-strike (ABS) challenge system work?

Home-plate umpires are still tasked with calling balls and strikes in games, but Hawk-Eye technology monitors the exact location of the pitch relative to the batter’s strike zone that is based on their height.

This allows players to ask for a challenge of a ball or strike call if they feel the umpire got it wrong. Each challenge must be made within two or three seconds of the umpire’s call.

Each team starts every Spring Training game with two challenges. However, only the batter, pitcher and catcher are permitted to ask for a review, and it must come immediately after the home-plate umpire’s call without any assistance from the dugout.

A player initiates an ABS challenge by tapping the top of their head. In the event that an umpire’s call is upheld, the team will lose its second challenge.

The ABS challenge system will only be used in Spring Training games this year — and the Minor League level — but some around MLB believe it could factor into regular season contests as soon as the 2026 season.