ABS is MLB’s name for an automated strike zone — also known as robot umps. In a full ABS game, there will be a human umpire behind the plate, signaling the calls communicated through ABS. We won’t be seeing that full system in action this spring. Instead, teams will have a limited amount of challenges.

Major League Baseball (MLB) is introducing robots to spring training this year on a trial basis in the form of the ABS (Alternate Ball-Strike System). ABS will peer over the home plate umpire’s shoulder to provide the right call if a team challenges the ump’s ball or strike call.

Starting Thursday at Camelback Ranch, where the Dodgers and Cubs will open Cactus League play, the ABS challenge system will begin being implemented.