MLB will test robot umpires at 13 spring training ballparks hosting 19 teams

Major League Baseball will test robot umpires as part of a challenge system during spring training at 13 ballparks hosting 19 teams, which could lead to regular-season use in 2026.

MLB has been experimenting with the automated ball-strike system in the minor leagues since 2019 but is still working on the shape of the strike zone.

An agreement for big league use would have to be reached with the Major League Baseball Umpires Association, whose collective bargaining agreement expires Dec. 1.

“I would be interested in having it in ‘26,” baseball Commissioner Rob Manfred said Wednesday after an owners’ meeting. “We do have a collective bargaining obligation there. That’s obviously a term and condition of employment. We’re going to have to work through that issue, as well.”

Manfred said the spring training experiment will have to be evaluated before MLB determines how to move forward.

“There’s two sides to that test," he said. "It’s what the clubs think about it and also what do the players think about it? And we’re going to have to sort through both of those.”

Triple-A ballparks used ABS this year for the second straight season, but there is little desire to call the strike zone as the cube defined in the rule book and MLB has experimented with modifications during minor league testing.

The ABS currently calls strikes solely based on where the ball crosses the midpoint of the plate, 8.5 inches from the front and the back. The top of the strike zone was increased to 53.5% of batter height this year from 51%, and the bottom remained at 27%.

After splitting having the robot alone for the first three games of each series and a human with a challenge system in the final three during the first 2 1/2 months of the Triple-A season, MLB on June 25 switched to an all-challenge system in which a human umpire makes nearly all decisions.

During the second half of the season, each team had three challenges in the Pacific Coast League and two in the International League. A team retains its challenge if successful, similar to the regulations for big league teams with video reviews.

“I think we will have a spring training ABS test that will provide a meaningful opportunity for all major league players to see what the challenge system will look like,” Manfred said. "It won’t be in every single ballpark but we actually have a plan where every team will get meaningful exposure.”