Here are Major League Baseball's ABS firsts

The 2026 baseball season is underway, which means that the Automated-Ball Strike (ABS) Challenge System, powered by T-Mobile, is getting its first official use at the Major League level.

In light of the historical significance, MLB.com will be keeping a running list of ABS firsts -- beginning, of course, with the first challenge ever issued in a regular season Major League Baseball game.

First challenge

Date: March 25, 2026
Game: Yankees at Giants (4th inning)
Player: José Caballero (NYY), batter

The first official ABS challenge was issued by Yankees shortstop Caballero on a first-pitch called strike from Logan Webb. The call on the field was upheld.

First successful challenge/first call overturned for a strikeout

Date: March 26, 2026
Game: Pirates at Mets (3rd inning)
Player: Francisco Alvarez (NYM), catcher

The first successful ABS challenge was initiated by Alvarez, the Mets catcher, on a 3-2 pitch that was initially called a ball. The call on the field was overturned, as Freddy Peralta's fastball was in the zone, resulting in a strikeout of the Pirates' Oneil Cruz.

First successful challenge by a batter

Date: March 26, 2026
Game: Twins at Orioles (2nd inning)
Player: Matt Wallner

With an 11.7% walk rate and a serviceable chase rate last season, Wallner is a pretty good judge of the strike zone. That paid off when Orioles starter Trevor Rogers dealt him a pitch that landed above the strike zone. It was initially called a strike, but Wallner challenged the call, which was overturned.

First challenge by a pitcher

Date: March 26, 2026
Game: Rangers at Phillies (8th inning)
Player: Zach Pop (PHI)

The only challenge by a pitcher on Opening Day came from the Phillies' right-handed reliever, who was certain his 3-2 pitch to the Rangers' Brandon Nimmo clipped the zone. Alas, the call on the field of a ball was upheld as the pitch did indeed land too far inside, resulting in a walk.

First successful challenge by a pitcher

Date: March 28, 2026
Game: Athletics at Blue Jays (8th inning)
Player: Hogan Harris (ATH)

Harris found himself in a jam in Toronto -- two runners on with no out in the eighth inning. His quick reaction to challenge this pitch -- called a ball to Ernie Clement -- turned a 2-1 count into a 1-2 count. Clement would end up flying out.

First call overturned for a walk

Date: March 26, 2026
Game: Twins at Orioles (4th inning)
Player: Josh Bell (MIN), batter

The Twins took four walks against the Orioles on Opening Day. That includes one that was confirmed by an ABS challenge. Once Rogers' 3-0 pitch against Bell was called a strike, Bell tapped his helmet to initiate a review that showed the offering missed up and away. Twins hitters challenged three calls on Opening Day and won all three.

First call overturned to end a game

Date: April 1, 2026
Game: Rangers at Orioles
Player: Samuel Basallo (BAL), catcher

With the Orioles leading the Rangers, 8-3, with two outs in the ninth, right-hander Albert Suárez delivered an elevated 1-2 fastball to Texas’ Evan Carter. The pitch was initially called a ball, but young Orioles catcher immediately challenged. The review showed that the pitch did hit the outside corner, resulting in a strikeout and the Major League’s first game-ending ABS challenge.