NEW YORK -- The more than century-old tradition of having a human umpire be the final authority on all ball-strike calls ended in the third inning Thursday at Citi Field, when Francisco Alvarez executed the first successful Automated Ball-Strike (ABS) challenge in a Major League game.
When home-plate umpire Adrian Johnson called a full-count pitch from Freddy Peralta to Oneil Cruz a ball, Alvarez immediately tapped his helmet, initiating the Mets’ first challenge. A review displayed on Citi Field’s center-field video board showed that the pitch had clipped the outside corner, resulting in a strikeout instead of a walk. The overturned call proved significant for the Mets, as Brandon Lowe homered two pitches later.
“I knew right away,” Peralta said after the Mets defeated the Pirates, 11-7, on Opening Day. “I thought that I tried to challenge it, but … he did it right away. I think that we were both on the same page. I was about to do it, too.”
ABS Challenge System, powered by T-Mobile
• See what happened on the first-ever ABS challenge
• Everything you need to know
• A visual guide to how ABS works
• Here are Major League Baseball's ABS firsts
• What does all the data mean
• Players get strike zones measured
• Player poll: Who'll be best at ABS challenges?
• ABS Challenge Dashboard
• ABS Challenge Leaderboard
Beginning this season, players have the power to appeal the strike-zone judgments of human home-plate umpires by turning to the ABS Challenge System powered by T-Mobile -- a technological advancement that helps ensure the most important calls are made correctly, while adding new strategy to the sport in the process.
The ABS system made its formal debut Wednesday in San Francisco on Opening Night, when Yankees shortstop José Caballero unsuccessfully challenged a strike call in the fourth inning of a game against the Giants. Alvarez’s challenge the following afternoon at Citi Field was the first successful one in MLB history.
Many players and fans are already familiar with ABS, which has been a part of Minor League Baseball since 2022. ABS was also used in Major League Spring Training beginning last year. It gained approval from the Joint Competition Committee last September for use in MLB games.
The ABS Challenge System tracks the precise location of each pitch relative to strike zone, which is calibrated to each player’s height and measured to a fraction of an inch. The system preserves the role of human umpires for the vast majority of pitches while providing a mechanism to correct the most obvious misses. A pitcher, catcher or batter can challenge a ball or strike call by tapping his hat or helmet immediately after the pitch. There is no input from the dugout.
Within seconds, the result is displayed on the stadium video board and broadcast to viewers, similar to in/out calls in professional tennis matches.
Teams spent Spring Training figuring out the best practices of who should challenge, as well as when it might be better not to challenge a suspected miss. Teams are only allotted two incorrect challenges per game, but they are given unlimited challenges so long as they continue to be correct. It may be wise, then, to forego an early challenge on a relatively unimportant pitch, saving it for higher-leverage situations later in the game. Some teams don’t give their pitchers the power to challenge, reserving it for catchers. The Mets are not in that camp, even though it was Alvarez who ultimately made the call against Cruz.
“We’re never 100 percent sure, but I think with the batter, it’s a taller batter so you know that his zone is a little bigger,” Alvarez said through an interpreter. “So with that one, I felt pretty confident about it.”