'Robot umpires' will debut in Major League Baseball in the 2026 season as the game adopts the automated strike zone challenge system tested in the 2025 pre-season, MLB announced on Tuesday.
MLB's joint competition committee voted to approve the Automated Ball-Strike (ABS) Challenge System, which allows players to challenge human umpires' ball and strike calls via an electronic system run by the Hawk-Eye technology already widely used in sports such as tennis.
The system had already been widely tested in the minor leagues before being tried in 2025 pre-season games.
In 2026, MLB teams will be able to challenge two calls per game and get additional appeals in extra innings. Only a pitcher, catcher or batter can challenge, without input from managers or players in the dugout.
Reviews will be shown as digital graphics on outfield video scoreboards.
Based on the system's use during spring training games, MLB reckons that challenges take an average of 13.8 seconds. If a challenge is successful, the team retains that challenge.
Umpires have been declaring pitches in or out of the strike zone since the birth of the sport in the 1800s, with plenty of disputes and argued calls since then.
MLB said in a statement Tuesday that the two-challenge system will be a "middle ground between so-called 'robot umps' that could call every ball and strike and the long-standing tradition of the natural human error that comes with human umps".
But it noted that the change will mark "the first instance within the championship season at the game's highest level in which the home-plate umpire's ball-strike calls will not be ironclad".