Smart Cameras Power a Robot Umpire at MLB All-Stars for the First Time. Here's How the Challenges Went

If umpires draw your ire for bad calls, you may soon have a new target: Major League Baseball used its ABS, or Automated Ball-Strike System, to call pitches at the July 15 All-Star Game for the first time. If trials this season go well, it will probably be adopted for the 2026 regular season. But challenges against the camera had an unusually high rate of success.

The ABS uses Hawk-Eye cameras, a technology increasingly common in games with high-speed objects. The cameras judge how a ball travels -- in this case, over the strike zone -- and are equipped to make a preliminary call.

A human umpire, along with batters and pitchers, have a couple of seconds to review the footage and challenge a call if they think the automated system was wrong. It's a system the MLB has experimented with since 2019 and is finally ready to bring to the national stage.

This approach has caused some controversy, particularly because the Hawk-Eye cameras are programmed to see the strike zone very differently from human umpires. Instead of the standard cube shape that's underpinned strike zone knowledge for decades, the ABS uses a two-dimensional rectangle standard that's automatically adjusted to extend between 53.5% and 27% of the batter's height. Batters are measured before each game.

The ABS didn't perform quite as well as it did in spring training -- or players are more willing to test it now. 

Todd Kirkland / Stringer via Getty

Those worried about discrepancies now have new fuel for their worries. In the July 15 game, which the National League won in a home run derby after nine innings ended with a tie, four out of five challenges to the ABS and umpire Dan Iassogna's combined work were successful. That's much higher than the ABS spring training test, where teams won only around 50% of their challenges.

The MLB hasn't revealed definitive plans on whether the ABS could replace umpires altogether, but at this time the human-based, real-time reviews from the umpire appear to be an integral part of the system.

The league did not immediately respond to request for comment.