An inning-ending strikeout became a game-tying RBI walk in about 15 seconds [CBS Sports]. During 2026 Spring Training, a batter challenged a called third strike through MLB’s new Automated Ball-Strike (ABS) Challenge System, and the technology confirmed the pitch was outside the zone. The call was overturned before most fans finished reacting to the original ruling.
Approved by the Joint Competition Committee on September 23, 2025, the ABS Challenge System now runs across all 2026 Spring Training, regular season, and postseason games. Early spring data is already exposing how often human eyes miss what cameras catch, and the numbers are harder to ignore than most expected.
From Minor Leagues to the Majors
The ABS system didn’t appear overnight.
MLB tested automated strike zone technology in the minor leagues for several seasons, refining the Hawk-Eye tracking system and gathering performance data before bringing it to the biggest stage. During those MiLB trials, the challenge success rate hovered around 49% [CBS Sports], meaning roughly half of all disputed calls were confirmed incorrect by the technology.
That progression from developmental leagues to the majors followed baseball’s classic pattern of cautious adoption. Instant replay took a similar path, debuting in limited form before expanding league-wide. ABS carries higher stakes, though: ball-strike calls happen hundreds of times per game, and each one shapes at-bats, innings, and outcomes in ways replay never touched.
How It Works on the Field
The mechanics are straightforward.
Photo by Each team gets a limited number of challenges per game. When a batter or catcher disputes a ball-strike call, the ABS system, powered by Hawk-Eye’s multi-camera tracking array, delivers a verdict within seconds. A successful challenge preserves your remaining challenges; a failed one costs you.
Key details from early implementation:
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Results arrive in roughly 15 seconds, faster than most mound visits [CBS Sports]
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The system tracked 88,534 pitches with only four going untracked [Cronkite News]
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Out of 1,214 challenges, just five instances lacked animation data [Cronkite News]
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The zone is tied to each player’s body and stance rather than a universal formula [CBS Sports]
That last point matters. Rather than applying a one-size-fits-all strike zone, ABS accounts for individual batter dimensions. It addresses one of the oldest complaints in the sport.
The Numbers Expose Real Gaps
Spring Training data has been blunt.
Photo by A striking 52.2% of challenges were successful [AOL], meaning more than half the time a player disputed a call, the technology sided with them over the umpire. Games averaged 4.6 challenges and 2.6 overturned calls per contest [AOL].
To put that in perspective: if a plate umpire’s borderline calls get challenged roughly five times a game and the machine overturns more than half, that’s a measurable accuracy gap on the pitches that matter most. One spring game saw seven challenges directed at plate umpire Alex MacKay alone [AOL].
These aren’t random errors scattered across the zone. Umpires struggle most on borderline pitches, where a 95 mph fastball crosses the plate faster than a human blink. The ABS data now quantifies what players and analysts have long suspected: certain pitch locations consistently fool the human eye.
Umpires Deserve Context Not Blame
None of this data suggests umpires are careless.
Photo by MLB umpires correctly call the vast majority of pitches, a remarkable feat given the cognitive demands of tracking a spinning ball arriving in fractions of a second. The errors ABS catches are concentrated on the most difficult calls, where human perception reaches its biological ceiling.
Aaron Judge has already used the challenge system this spring [MLB.com]. His willingness to engage with ABS signals that players view it as a fairness tool, not an attack on umpires. The system functions more like a safety net than a replacement, catching the calls that fall through the cracks of human judgment.
“The new zone will mean each player’s strike zone is uniquely tied to their body and stance rather than a universal formula.” [CBS Sports]
Where Baseball Goes From Here
The 2026 season represents the largest live deployment of ABS technology in major professional baseball.
Photo by With the challenge system embedded in every game from February through October, MLB will accumulate a substantial dataset on umpire accuracy, challenge behavior, and game-flow impact.
The trajectory points toward a fully automated strike zone eventually, with the challenge model serving as the trust-building bridge. Players get accustomed to the technology. Fans learn to read the on-screen animations. Umpires adapt their positioning knowing every borderline call faces potential review.
Baseball has always evolved slowly, from hand-scored box scores to Statcast. ABS fits that pattern, arriving not as a revolution but as the next logical step in a sport that’s finally letting technology confirm what the human eye has always struggled to see.
Early spring numbers, a 52.2% overturn rate and nearly five challenges per game, confirm that umpire blind spots on borderline pitches are real, patterned, and now measurable. The technology doesn’t diminish the umpire’s role; it strengthens the integrity of every at-bat. Watch the challenge moments during the 2026 season. Each overturned call is a small piece of baseball history being rewritten, one pitch at a time.
