Statcast Breakdown: MiLB ABS Analysis

Long live the robots. The robots are here to stay.

After trial runs in both Triple-A and spring training, the Automated Ball Strike Challenge System [ABS] has made its way to the big leagues in 2026.

Starting on Opening Day 2026, players have been able to turn to ABS to issue a final judgment on close ball/strike calls. ABS is the first system to take away unilateral ball/strike decision-making from the home plate umpire’s discretion. Now, batters, pitchers, and catchers are granted an opportunity to challenge an egregious ball or strike call.

Once a player requests a challenge by tapping his helmet, 12 strategically placed Hawkeye cameras review the pitch’s location, and either overturn the on-the-field call or confirm the initial decision. Teams are granted two “challenges” per game, and retain the challenge if a call is overturned.

Early returns show ABS pretty evenly split on each side. As of publishing on March 31 before gameplay, 55% of challenges have been overturned. (Batter sit at 50% and pitchers and catchers sit at 58%.)

This change, the latest to incorporate cutting-edge technology into on-the-field play, will have major ramifications on the sport’s strategy.

Consider the delta in run value when a ball is called on the first pitch of an at-bat, compared to a strike. According to Baseball Savant, batters who started an at-bat with a 1-0 count were more productive by 9 runs, compared to batters who started with a 0-1 count. Nine runs are estimated to be worth an extra win, underscoring the importance of ensuring the accuracy of every single pitch.

Not every questionable call strike will be worthy of a challenge. Some teams may only use their objections at leveraged moments, such as when the game is on the line in the later innings.

Incorporating ABS into the granularities of calling balls/strikes represents a paradigm shift from the antiquated technologies that previously proliferated MLB.

In the mid-2000s, Pitchf/x emerged as the first regulated system to provide simple insight into pitch metrics, such as velocity and location. In the years since, TrackMan & Hawkeye have become virtually household names by disseminating new levels of pitch data at a rapid pace and furthering our understanding of “what makes a pitcher good.”

The Mets seemed primed to face any early ABS issues. Earlier this spring, Carlos Mendoza relayed the club’s spring training ABS strategy to the NY Post:

Asked how the team would approach the new rule this spring, the manager said, “Be aggressive. Challenge as much as possible. We want to see who’s good and who’s not [at challenging].”

While numbers in the spring should be taken with a grain of salt, and despite the guidance from their skipper, the Mets’ batters challenged only 19 times in the Grapefruit League; six were reversed. Their backstops tapped their heads 27 times, reversing the call 13 times.

Marcus Semein, Kevin Parada, and Christian Pache each led the club with three challenges; Semein and Pache overturned a call apiece while Parada was unsuccessful in his trio of attempts.

A handful of Syracuse Mets, projected to receive time with the big-league club in 2026, used ABS in 2025. Thanks to Baseball Savant’s new functionality, we’re able to identify the Mets players, a step away from the Majors, who were strong in their decisions to challenge ball-strike calls in 2025.

Veteran journeymen Gilberto Celestino & Yonny Hernandez each led the Syracuse Mets with 10 overturned challenges, with Hernandez’s 56% successful challenge rate just eeking out Celeistin’s 50%. Hernandez led the club with +2.7 “Net For” challenges, which gives a player credit for overturns on pitches thrown in similar locations to other players.

Celestino challenged at more opportune times. He had three strikeouts negated by a correct overturn on a strike outside the zone, while once correctly challenging a strike on a three-ball count.

Several Syracuse Mets hitters, who either previously garnered extensive major-league time or are projected to in 2026, familiarized themselves well with the challenge system in their debut season with ABS. Even with the small-sample caveat, Jesse Winker, Mark Vientos, and Jose Siri ranked in the team’s top three in “Challenge Rate vs Expected”, which takes into consideration the challenges a player is expected to win.

The club’s top hitting prospects in Triple-A, namely Jett Williams, Ryan Clifford, and Luisangel Acuna, overturned four calls in six tries.

Overturning calls via ABS isn’t just an option for hitters; pitchers are able to utilize it to reverse egregious ball/strike counts. During his time leading the Mets’ AAA staff, Nolan McLean‘s pitches were challenged 17 times by the Mets, with seven overturned. His seven reversals ranked second among Mets’ pitchers, trailing only former Mets farmhand Brandon Sproat.

A plethora of the Mets’ top pitching prospects, including McLean, got accustomed to ABS in 2025, a relieving note given the Mets tend to yo-yo pitchers between their Triple-A and big league rosters. McLean, Austin Warren, and Jonathan Pintaro, all members of the Mets’ current 40-man roster, each won three challenges in 2025.

Despite the individual success stories, when compared to the league, the Syracuse Mets, as an aggregate, performed poorly at overturning calls. In 2025, Syracuse won only 46 challenges, placing last in the International League. Their -42 expected net overturns ranked second-to-last in the minors, while 36% overturn rate trailed none.

Give Angel Hernandez his flowers. Calling ball/strikes isn’t an easy job to do. The nuances required, combined with 40,000 fans watching the real-time result, make this task a particularly grueling one. ABS provides a fix to baseball’s toughest job by putting the onus on the players to correct any inaccurate calls.

If you’d like to pull ABS data to an Excel file programmatically, via Python, please follow this request.

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