It's not quite robo umpires but hitters and pitchers can challenge balls and strikes calls by umpires in certain stadiums this spring as a test.

For the first time in MLB history, a pitch was challenged using the new Automated Ball-Strikes system — and the call on the field was overturned.

There are no immediate plans to introduce the system in regular-season games yet. Questions remain about how large a role it should have in games that count.

This spring training will introduce a new element to the action: for the first time, MLB will employ the automated ball-strike system (ABS for short) during big-league contests. ABS is, for those unfamiliar with the concept,

The Automated Ball-Strike System (ABS) challenge got its first test run in big league Spring Training on Thursday afternoon, with two challenges taking place in the Cactus League opener between the Cubs and Dodgers.