Royals home Spring Training games to feature strike zone challenge system tests

What it is, how it works, why it is the way it is, and what comes next

For the past few seasons minor league baseball has been testing a new strike zone challenge system called Automated Ball Strike Challenge System or ABS. This year, for the first time, the system will be tested out at the Major League Level. In fact, it was tried out for the first time yesterday during the first matchup of the spring between the Dodgers and Cubs.

What is ABS?

The ABS system uses a series of cameras (called Hawk-Eye cameras, which endears them to me immediately) working in concert to determine where a given pitch crosses the strike zone. These cameras are currently only present in some stadiums – in the Cactus league those stadiums include Salt River Fields, Peoria Stadium, Camelback Ranch, Goodyear Ballpark, and the Royals’ own Surprise Stadium. So only about 60% of Spring Training games will allow for challenges. Each team will receive two challenge failures, meaning that as long as they challenge correctly they can keep challenging, but once they’ve missed twice that’s it.

Only the pitcher, batter, or catcher can challenge. As you can see in the embedded post above, the challenges are performed very quickly. One of those three players taps their head to request a challenge and it can be completed in under a minute. As to why a challenge system is being used instead of simply allowing the so-called RoboUmp to make all the calls, one of the reasons is that survey research showed that 61% of players and MLB staff surveyed preferred that setup.

One of the changes fans might most notice with the ABS system is that TV broadcasts may no longer show the approximation of the strike zone that has become ubiquitous in recent years, allegedly because then fans would already know the likely outcome of any challenges.

2. The home viewer’s entertainment experience. If a reasonable approximation of the automated strike zone is available to viewers and a player issues a challenge, the viewer will already know the correct call prior to the system’s review. The fun of the challenge system is that anxious moment (and if you’ve witnessed the ABS challenge system, you know it’s only a moment) between when the player asks for the challenge and the system’s conclusion is shown on the scoreboard and broadcast.

Evan Drellich of The Athletic included this somewhat confusing quote in his own article on the subject:

“The strike-zone box that we display on broadcasts and our app probably is inconsistent with the way we currently do it with the challenge system,” said Morgan Sword, MLB’s executive vice president for baseball operations, at a press conference Tuesday. “You take a lot of the drama and excitement out of it if the fan can see up front that that pitch was a strike. It sort of obviates the need for the challenge.

I don’t need an anxious moment between a challenge being requested and finding out the answer to improve my viewing experience. I don’t think most of us do, but that appears to be MLB’s position. Still, I really wish Drellich had pressed Sword on the idea that it somehow was incorrect but also told fans all the answers ahead of time. In any case, should they implement such a change fans should complain. Complain about it enough, and perhaps MLB will revert, as they did when fans and players complained about last year’s uniform changes.

Is the home plate umpire obsolete?

First of all, while MLB is testing the system in Spring Training this year, it will not be in use during the regular season. But even if it’s implemented in 2026 (which I, personally, expect) home plate umpires have many duties beyond calling balls and strikes. They’re responsible for ruling whether any ball that doesn’t make it past the bases is fair or foul, for calling catcher’s interference, hit by pitch, tag plays at the plate, and more.

If you’re wondering if this is the beginning of umpires becoming obsolete in general, letting cameras and sensors determine everything that happens on the field, I wouldn’t bet on it. Such technology is expensive, finicky, and prone to breaking. If you put sensors in balls, every foul ball and home run becomes significantly more expensive. Bats shatter all the time. Given the non-spherical shape of everything on a field other than the ball, all other objects would require multiple sensors as well. And even if MLB was willing to accept all of that, there would inevitably be instances of technological failure that would require human umpires to be able to intercede.

ABS is almost certainly not the perfect solution to MLB’s strike zone problem, but there may be no perfect solution. Shifting to a purely automated solution won’t remove all questions of objective correctness. Fans have screamed for years that umpires need glasses, if MLB switched to a purely automatic ball-strike calling system fans would certainly begin questioning the calibration of the cameras in use instead.

Let’s be honest, we all already know technology doesn’t immediately resolve every bad call it touches.

So no, this system isn’t perfect, but it’s probably better than what we currently have. It should be less invasive than the already-present replay review system, too. I’m excited to see it tried out in Spring Training, and even more excited to see it implemented in regular season and postseason games next year.