Commissioner Rob Manfred was "completely inaccurate" when he said MLB would be using an electronic strike zone in exhibition games this spring, according to the Major League Baseball Umpires Association.
The umpires' union clarified that automated balls-and-strikes software (or an electronic strike zone) would be used behind the scenes during nine spring training games. The on-field umpires will make all rulings during the games as usual.
Manfred had announced:
We're going to be using it during spring training and in some of our minor leagues this year. The way it works is the camera calls the ball or strike [and] communicates to an earpiece that the umpire has in his ear.