The Almost-Immaculate: Henry Davis and the ABS Challenge Gamble

In the closing moments of a 16-5 blowout victory over the Washington Nationals on Monday, April 13, the Pittsburgh Pirates found themselves in a situation where the stakes were nonexistent, but the history was tantalizing. Left-handed pitcher Evan Sisk, making his 2026 debut after a call-up earlier that day, was on the verge of an immaculate inning—the rarest of feats in baseball.

Sisk had already dispatched Keibert Ruiz and Joey Wiemer on a combined six pitches. When he faced Luis García Jr., he quickly worked ahead to two strikes. The stage was set for the second immaculate inning of the 2026 season, which would have seen Sisk join the Arizona Diamondbacks’ Michael Soroka, who achieved the feat on March 30.

Then came the pitch: a 78.5 mph sweeper. The ball broke across the plate but dipped low and away. It was a clear ball, and García Jr. Took it. However, catcher Henry Davis, recognizing the historic opportunity, opted to use the ABS challenge system. Davis presented the ball to home plate umpire Sean Barber for a brief moment before tapping his helmet to initiate the challenge.

The result was predictable. The challenge was upheld, with the system confirming the pitch missed the strike zone by 2.8 inches. While Davis took a hit to his successful challenge record—which had started strong at 5-for-7 this season—the attempt was viewed as a great-natured gamble in a game already decided.

Understanding the ABS Challenge System

The Automated Ball-Strike (ABS) challenge system, powered by T-Mobile, was implemented by Major League Baseball for the 2026 season to bring more precision to the strike zone. The system utilizes the same Hawk-Eye tracking technology that fuels MLB’s Statcast data to determine whether a pitch was actually a strike or a ball.

For those unfamiliar with the mechanics, the process is strictly limited to specific personnel. Only batters, pitchers, and catchers are permitted to initiate a challenge. Managers, coaches, and other players are barred from interfering with the process.

The rules regarding challenge volume are designed to prevent constant interruptions:

• Each team starts the game with two challenges.
• If a team wins a challenge, they retain their ability to challenge.
• If a team challenges incorrectly twice, they lose all remaining challenges for the rest of the game.
• In extra innings, teams receive a fresh challenge regardless of their previous status in the first nine innings.

One notable restriction is that challenges are not permitted when a position player is pitching, ensuring the system remains focused on professional pitching standards.

The Science of the Strike Zone

The ABS zone is not a generic box; it is tailored to the individual batter. While the width is fixed at 17 inches—matching the width of home plate—the height is dynamic. The top of the zone is set at 53.5% of a player’s measured height (without cleats), and the bottom is set at 27% of that same height.

Crucially, the system captures the ball as it passes through the middle of the plate rather than the front, providing a consistent point of measurement for every pitch.

Performance Trends: Who is Winning the Challenges?

As the 2026 season progresses, data from the ABS challenge system tracker reveals a distinct gap in success rates between hitters and fielders.

the system shows a 55% overturn rate, with 530 calls overturned and 441 confirmed across 971 attempts. However, the breakdown by role shows that fielders (pitchers and catchers) are significantly more accurate in their challenges than batters.

This disparity suggests that catchers and pitchers may have a better intuitive feel for the ABS zone’s boundaries, or perhaps a higher incentive to challenge borderline pitches to maintain momentum.

The Human Element in a Digital Era

The incident involving Henry Davis highlights a fascinating intersection of technology and the “game within the game.” In a tight, high-stakes playoff race, a catcher would rarely risk a challenge on a pitch that is “clearly a ball.” But in a 16-5 blowout, the ABS system became a tool for a bit of sporting whimsy.

Davis’s willingness to challenge a known ball for the sake of a teammate’s potential history underscores the lighter side of the 2026 season. While the data-driven nature of the Hawk-Eye system removes the umpire’s subjectivity, it hasn’t removed the players’ desire to chase legendary milestones.

For Evan Sisk, the debut was still a success. He shut out the Nationals in the eighth and ninth innings, recording three strikeouts and allowing only one hit, even if the immaculate inning remained just out of reach.

The MLB continues to track these metrics to refine the system. As players grow more accustomed to the 53.5% and 27% height thresholds, the “challenge rate”—defined as challenges initiated out of potential non-swing takes—is expected to evolve.

The Pirates and Nationals will continue their series, with the league monitoring the ABS leaderboard to see which teams and umpires are adapting most effectively to the automated era.

Stay tuned to Archysport for further updates on the MLB ABS challenge rankings and season milestones.