JUPITER, Fla. – One big change for the St. Louis Cardinals’ spring training experience this year is the arrival of an automated ball-strike system (ABS), unofficially known by some as robot umpires.
TrackMan’s ABS system is a high-tech upgrade that allows players to challenge umpire calls in real-time. It has been used in minor-league baseball for several years, but this spring marks a key test to determine whether it could become a permanent fixture in Major League Baseball next year.
ABS relies on a set of cameras to track pitch location and evaluate each hitter’s personalized strike zone.
If a pitcher, catcher, or hitter questions an umpire’s ball or strike call, they can tap their helment or cap with two hands immediately after a call to request an ABS challenge.
However, challenges must be made before the next pitch and without guidance from the manager or dugout. Human umpires have the authority to deny a challenge if it doesn’t directly come from a pitcher, catcher, or hitter actively involved in the at-bat.
If ABS determines that the ball touched any part of the strike zone when it was originally called a ball, the call is overturned to a strike. If it reveals that a baseball is entirely outside of a strike zone when it was originally called a strike, it will be overturned as a ball.
Each team begins the game with two challenges. A successful challenge is retained, while an unsuccessful challenge is lost. Teams will not be rewarded with extra challenges if a game goes into extra innings. The goal is to encourage players to use challenges strategically in moments where a call could significantly impact the game or an at-bat, rather than challenge repeatedly to get calls in their favor.
Major League Baseball says the strike zone dimensions will include…
- Plate width: 17 inches (consistent for all hitters)
- Strike zone depth: 8.5 inches (consistent for all hitters)
- Top of the zone: 53.5% of the player’s height (varies by hitter)
- Bottom of the zone: 27% of the player’s height (varies by hitter)
Major League Baseball will not extend ABS beyond spring training in 2025, but if feedback is generally positive, the system could be implemented in regular-season games by 2026. This spring also serves as an opportunity to refine ABS at the minor-league level, where the challenge system became an everyday part of the game last summer.
While the Cardinals haven’t used ABS challenges extensively this spring, manager Oli Marmol has encouraged players to test it out when it feels necessary. Outfielder Lars Nootbaar became the first Cardinal to successfully challenge an umpire’s call in one of their first spring games. ABS confirmed the pitch was nearly two inches outside of Nootbaar’s strike zone, overturning the call from a strike to a ball.
Nootbaar told the St. Louis-Post Dispatch it was a challenge he felt was necessary to avoid a stirkeout with two runners on base and one out. He added, “Pretty cool to get rewarded for that,” though he also noted that he isn’t ready for MLB to fully replace human umpires with automated calls, as tested in some minor-league games with ABS.
Many of Nootbaar’s Cardinals teammates shared the same sentiment, especially pitchers who are familiar with ABS from the minor-league level. Several shared their thoughts with FOX 2.
MICHAEL MCGREEVY
“I can tell from experience that if you’re getting all the calls, if you’re clipping the zone with the ABS, you’re having a great day, and if you’re getting every challenge right, you’re having a great day. But some of those days where hitters know the zone like the back of their hand. It gets tough because these hitters just get better and better the higher up you go and know their zone. So if you’re not getting off the hook with a strike call that’s maybe a ball off, you’re in for a long day. It definitely makes it tough. I enjoy the human element of it, but baseball is a changing game, and whatever they do is going to be fine, but I hope they stick to the regular strike zone.”
RYAN LOUTOS
“I pitched with ABS a lot the last few years. I really like the challenge system. I think it’s great. I think there’s a lot of pitchers that will be surprised with how small the zone actually is. That was a big surprise pitching in Triple-A last couple of years. The umpires tend to give a little more on the corners than the straight ABS, but with the challenge system, I think it will be great. It will keep the human element of the umpire while still keeping everyone accountable and hopefully not letting bad calls change the outcomes of games.”
JOHN KING
“I like it. As a sinker guy, I do like the umpire calling it more because if you keep hitting a spot, I feel like the zone expands a little bit with a ball that runs east to west. For me, I’d rather have the umpire, but I still think it’s great. I think the challenge system makes it entertaining for fans at times, especially in a big situation, but to be on the losing side of that too, it can be tough if you make a good pitch barely out of the zone. But I think it’s good. I like it.”
GORDON GRACEFFO
“We played with it the past two years down in Memphis. I like it. I think it’s better than the automatic zone by itself. I like the fact that the umps still call the game, but there’s a little bit of keeping the zone in check with challenges.”