MLB to Introduce “Robot Umpires” with ABS Challenge System in 2026

Major League Baseball is set to usher in a new era of officiating beginning in the 2026 season, with the approval of an Automated Ball-Strike (ABS) Challenge System, commonly dubbed “robot umpires.” The decision was made by MLB’s 11-member Joint Competition Committee, which includes team representatives, players, and an umpire.

Under this hybrid model, human umpires will continue to make the initial calls on balls and strikes. However, pitchers, catchers, or batters will be allowed to challenge such calls by tapping their helmet or cap immediately after the ruling.

Each team will receive two challenges per game, and in extra innings, teams that have no remaining challenges will be granted one.

If a challenge is successful, the team keeps that challenge; if not, it is lost. The review results will be displayed via digital graphics on stadium videoboards and on broadcasts.

This isn’t a completely new idea: MLB has been testing ABS technology in Minor League Baseball since 2021 and more extensively in Triple-A games since 2022.

The system also underwent trials during Spring Training and the 2025 All-Star Game, with generally favorable feedback from players.  Those earlier tests helped refine the strike zone definitions, camera setups, and operational timing.

The ABS strike zone is calculated using a fixed two-dimensional plane across home plate (17 inches wide), with its top set at 53.5 % of the batter’s height and the bottom at 27 % of height. The system determines the call based on where the ball crosses the midpoint of the plate, not by where it might pass any part of the three-dimensional zone.

In 2025’s Spring Training and All-Star Game, operators averaged about 4.1 challenges per game, with an overturn rate near 52.2 %. Interestingly, catchers achieved the highest success rate (~56 %), followed by hitters (50 %) and pitchers (41 %). These metrics closely mirror those seen in Triple-A ABS usage.

The move is perceived as a balancing act: it aims to reduce controversial calls and heated ejections over balls and strikes while still preserving human elements like pitch framing and the presence of on-field umpires.

In recent years, a large portion of ejections have stemmed from disagreements over ball/strike rulings — statistics show 61.5 % of ejections in 2024 and 60.3 % in 2025 were tied to such disputes.

There is still skepticism, especially from some players and observers who question whether ABS will align perfectly with existing strike-zone expectations or if it may diminish catcher strategies.

Player representative Austin Slater, a member of the competition committee, cautioned that no technology is flawless and emphasized the importance of preserving pace and fairness.

Overall, MLB’s approval of robot umpires marks a significant shift in how games will be officiated — blending technological precision with traditional judgment, at least for now.