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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.

Here is what every big leaguer needs to know about ABS, according to players and managers who have experience with it in the minor leagues.