MLB Introduces Automated Ball-Strike System in 2025 All-Star Game

Major League Baseball (MLB) is set to introduce the Automated Ball-Strike (ABS) system, commonly referred to as "robot umpires," during the All-Star Game at Truist Park in Atlanta on July 15, 2025. This marks the first use of ABS in an MLB All-Star Game, following extensive trials in the minor leagues since 2019.

The ABS system employs advanced technology to determine balls and strikes, aiming to enhance accuracy and consistency in officiating. Each team will have two challenges per game, retaining them if successful. The system defines the strike zone based on a percentage of the batter’s height, differing from the traditional cube-shaped zone used by human umpires.

The journey of ABS began in 2019 when the independent Atlantic League first employed it during its All-Star Game. Umpires received ball-strike calls via earpieces using TrackMan technology, allowing them to make calls based on automated messages or their discretion in case of system malfunctions. Subsequent implementations included the Arizona Fall League in 2021 and the Florida State League in the same year. By 2022, ABS was introduced in five Triple-A stadiums and expanded to all stadiums at that level by 2023. The Korean Baseball Organization (KBO) became the first professional league to implement ABS during its 2024 season.

The ABS system utilizes Hawk-Eye technology to track the exact location of each pitch. The strike zone is defined as a three-dimensional space, with the width set at 17 inches (matching home plate) and the height adjusted based on a percentage of the batter's height—53.5% for the top and 27% for the bottom. The system makes its decision when the ball is at the midpoint of the plate, 8.5 inches from the front and back. Notably, the ABS strike zone does not change based on the batter's stance.

During the 2025 Spring Training, the challenge system allowed only the batter, pitcher, or catcher to challenge a ball or strike call by tapping their cap or helmet immediately after an umpire's call. Each team was allotted two challenges per game, retaining them if successful. Players had to make the decision independently, without assistance from coaches or managers.

Reactions to the ABS system have been mixed. Pitchers like Paul Skenes and Clayton Kershaw have acknowledged the system's accuracy and adaptability to different batter sizes. Kershaw stated, "I did a few rehab starts with it. I’m OK with it. I think it works." However, some players and managers prefer delegating challenge decisions to catchers and managers. During Spring Training, challenge success rates were 56% for catchers and 41% for pitchers.

Reds manager Terry Francona opted out of participating in the ABS trial during Spring Training, allowing minor-league players familiar with the system to utilize challenges. He believed the system was not a strategic fit for major league teams and did not contribute to season preparation.

The introduction of ABS in the All-Star Game signifies MLB's commitment to integrating technology to enhance officiating accuracy and consistency. This move reflects broader societal trends toward automation and data-driven decision-making. However, it also raises questions about the human element in sports and the potential impact on the traditional roles of umpires. The system's implementation may influence how fans perceive the game, potentially reducing disputes over controversial calls but also altering the dynamics of player-umpire interactions.

Commissioner Rob Manfred anticipates the system will be reviewed by the competition committee, with potential implementation in the 2026 regular season. Hall of Famer Joe Torre supports the change, citing past playoff games where human error significantly impacted outcomes. Torre remarked, "You couldn’t ignore it with all the technology out there."

The debut of the ABS system in the 2025 MLB All-Star Game represents a significant milestone in the league's ongoing efforts to modernize and enhance the accuracy of officiating. While the system promises increased consistency in ball-strike calls, it also prompts a reevaluation of the traditional roles within the game and the balance between human judgment and technological precision. As MLB continues to assess the system's effectiveness, the 2025 All-Star Game will serve as a critical test case for potential broader implementation in future seasons.