Everything Yankees' Jose Caballero, Boone Said About Losing 1st-Ever ABS Challenge in MLB History

New York Yankees shortstop José Caballero made history on Wednesday night as the first MLB player to challenge a call using the automated ball-strike system in a regular season game during a 7-0 win over the San Francisco Giants.

Caballero gave the signal to challenge a strike call in the top of the fourth inning, but it backfired on him because the call stood when review determined the ball hit the upper end of the strike zone.

"I wanted to go for it," Caballero said of his unsuccessful challenge after the game. "I thought it was a little higher than what it showed. But at least it was close."

Yankees manager Aaron Boone supported Caballero's decision to challenge, saying the pitch was "really close" and explaining he thinks the players will get better at it as they get accustomed to the system:

"I feel like we're going to be good at it. That's the expectation. I'm sure we'll continue to evolve with it. My thoughts on it now maybe are a little bit different than even at the start [of camp], somewhat. So I would imagine as the season unfolds, those things will continue to evolve and we'll try to exploit it as best we can."

The ABS system isn't wholly new to players currently in MLB since it has been used in the minors since 2022. The league also tested it out for big league players for the first time in spring training last year.

Per MLB.com, the system uses Hawk-Eye cameras that are set up in dedicated locations throughout all 30 MLB stadiums to track the movement of the baseball.

The automated strike zone is determined using a player's specific height. The top of the zone is set at 53.5 percent of their measured height, while the bottom of the zone is at 27 percent.

Since it is all automated based on a specific criteria, the results of the challenge are determined in seconds. The closest parallel in sports is the challenge system in tennis, which also uses Hawk-Eye camera technology.

Pitchers, catchers and batters are the only ones allowed to call for a challenge. It must be signaled for immediately after the pitch is thrown and the umpire makes a ball or strike call.

Teams are allotted two challenges at the start of each game and can retain them if they are successful.

Given that there were a combined 248 pitches thrown between the Yankees and Giants on Wednesday night with only one of them being challenged, it was a good night overall for home plate umpire Bill Miller.