When the Atlantic League’s computer umps look at the strike zone, they see a different one than the zone called in the majors and minors.
As it currently stands, the computerized strike zone is taller and narrower than the one that human umpires normally call.
Pitchers can get high strikes from the computer that they do not get from human umps. The computer treats a 3-0 pitch and an 0-2 pitch the same, while human umpires generally expand the zone on 3-0 counts and pinch their strike zones on 0-2 counts.
The human strike zone is more oval shaped than a rectangle, while the computer calls a zone with four distinct corners. So as it currently stands, there are pitches that the computerized strike zone calls as strikes that seem to be balls to the naked eye.
In the Atlantic League, there are pitchers whose careers have benefitted from robo-umps (pitchers with a quality fastball they can locate up in the zone have thrived) and others who saw their ERAs explode (pitchers who try to work in and out generally have struggled).
But there’s an important aspect missing from this debate. When you design an automated strike zone, everything about the strike zone becomes a programming problem.
Want the strike zone to be wider? Just make it wider. The zone can be programmed so that the zone stretches an extra half-inch, an inch or six inches beyond the black of the plate. That could be done on both sides, or only on the outer half. It’s doable, if that’s what baseball wants to do.
Theoretically, MLB could even make the 3-0 strike zone bigger than the 0-2 strike zone. It’s all about what decisions are made.
Want to make it completely uniform? Baseball could set a fixed strike zone that remains in place no matter who is at bat. Aaron Judge and Jose Altuve could bat with a strike zone that is exactly the same.
Want to make it more oval-shaped like the current zone? It can be programmed. Want to take away the high strike? It’s a couple of clicks after MLB makes the decision to do so. If for some reason MLB wanted to encourage crazy breaking balls, it could make a rule where a ball crossing the zone at any point in the entire depth of the strike zone is a strike. If it wants to discourage those pitches, it can say they have to cross the front of the plate in the zone (which is what they are currently doing in the Atlantic League).
The strike zone has rarely, if ever, matched the zone defined in the rule book. Back when American League umpires used balloon protectors and the National League umpires didn’t, the two leagues had different strike zones (AL umps were thought to have bigger strike zones).
The strike zone has become more uniform over the past 20 years, as MLB has pushed grading to try to get umpires to call a more standardized strike zone.
But if MLB ever does adopt computerized strike zones, it will have to ask an important question: Does it want to try to replicate the human strike zone as best it can, or would it prefer to set up a new and different strike zone?
There’s no clear answer to that one, but if robo-umps are around the corner, it will make for a very interesting debate.