Major League Baseball to Introduce Automated Ball-Strike System Starting in 2026

Unlike in Korea, will adopt the 'challenge' system to appeal umpire ball calls.

Video of ABS call verification appearing on a scoreboard during an MLB exhibition game in March of this year. [AFP=Yonhap News]

Major League Baseball (MLB) will introduce the Automated Ball-Strike (ABS) system starting with the 2026 season.

U.S. media outlets, including the Associated Press and MLB.com, reported on the 24th (Korean time) that "the MLB Competition Committee, comprised of 11 members, has approved the introduction of ABS starting in the 2026 season," adding that "the home plate umpire will still call balls and strikes from behind the catcher, and each team will be allowed to challenge calls twice per game."

However, it is understood that the discussion results were not unanimous.

The Competition Committee consists of six club officials, four players, and one umpire representative. Among the four players, one voted against it, and the umpire representative's vote (for or against) is unknown. All six club officials voted in favor.

While all pitches are called by ABS in the Korea Baseball Organization (KBO), MLB differs significantly by adopting a 'challenge' system where a team can appeal the umpire's ball and strike calls, which are then verified by ABS.

Furthermore, appeals for pitch calls can only be made by the pitcher, catcher, or batter by tapping their caps. Managers are not permitted to make challenges.

Batters, pitchers, and catchers must challenge an umpire's strike or ball call immediately after it is made, without assistance from teammates in the dugout. If a challenge is successful, the number of challenges allowed will not be deducted.

If a game goes into extra innings, an additional opportunity will be given for each extra inning played.

MLB.com explained that the 'challenge' format was adopted instead of entrusting all pitch calls to the system, allowing for the continued coexistence of the human element of an umpire officiating games, which baseball fans and professionals still desire, and the catcher's framing (the technique of catching a pitcher's ball to make it appear as a strike), which was developed after extensive research.

Based on statistics gathered from pilot operations of ABS in the minor leagues and independent leagues since 2019, the MLB office has decided to implement it in the major leagues starting next year.

The Atlantic League, an independent league, piloted ABS during the 2019 All-Star Game, and MLB introduced ABS in the Arizona Fall League, primarily featuring prospects, in the same year.

Additionally, ABS began being used in Triple-A of the minor leagues in 2022.

Citing the statistical website UmpireScorecard, the Associated Press reported that "the accuracy of home plate umpires' strike calls in the big leagues is approximately 94%."

It also predicted that "the introduction of these robot umpires will reduce ejections during games."

According to MLB statistics, 61.5% of ejections are related to ball and strike calls.

In Triple-A this year, there were 4.2 challenges per game, and the success rate of challenges was 49.5%, nearly half.

Challenges by the defensive team were successful 53.7% of the time, and challenges by the offensive team were successful 45% of the time. Yonhap News