Robo Ump (ABS Challenge System) Debuts at MLB Spring

Baseball's electronic 'robo ump' Automated Ball/Strike System (ABS) debuted in MLB Spring Training and it took only a half inning before Chicago challenged HP Umpire Tony Randazzo's ball call, with ABS overturning it to a strike. Here's how ABS will work during its MLB Spring Training experiment and what that could mean for the future of TV's on-screen strike zone box graphic.

MLB brings the formerly Triple-A ABS challenge system to select Spring Training games in 2025, reducing team challenges to two per club (down from three in Triple-A). As is the case in Triple-A, only a batter, catcher, or pitcher may challenge a ball or strike call and the challenge request (indicated by tapping one's head) must be made immediately after the call in question. Teams lose their challenges with an unsuccessful challenge while they retain their challenges if the review results in an overturned call.

Taking a 17-inch wide home plate, ABS calculates every batter's strike zone the same way: the bottom of the zone stands at 27% of a batter's height, while the top is 53.5% of their height, regardless of where their actual hollows-beneath-the-knee and midpoint-between-belt-and-shoulders actually line up.

ABS also calculates the depth of home plate a little differently than TV. Whereas TV broadcasts display the ball's projected location at the front edge of home plate, ABS uses the middle of the plate's depth (the back edge of the plate's rectangle portion / base of triangle vs. TV's front edge).

In other words, ABS does not address the 2D vs 3D strike zone problem nor does it address the issue of fluctuating zone height in real-time, but it appears to serve more as a game management tool than one of absolute accuracy: the hope is that teams will buy in to ABS and if it's successful in that regard, it won't matter if ABS is actually accurate because the players and managers will accept it on its face alone.

MLB has indicated it may no longer be a fan of television's graphical strike zone, since TV's methodology conflicts with ABS: the league is concerned discrepancies between TV and ABS might make it harder to sell fans and teams alike on the challenge system. Will ABS spell the end of K-Zone on TV? Will it matter that ABS makes incorrect calls sometimes? Stay tuned...

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Alternate Link: MLB Debuts Electronic Strike Zone Challenge System in at Spring Training Game