In his start in the Arizona Fall League’s annual Fall Stars Game, Royals prospect Daniel Lynch was extremely impressive. The 6-foot-6 lefthander whiffed two hitters in a scoreless inning and showed a fastball that reached 99 mph.

Because the game was played at Salt River Fields, the first strikeout came with a little bit of an asterisk. The park utilized the TrackMan-enforced strike zone for the AFL’s six-week season, which led to some interesting calls.

Lynch opened the Fall Stars Game with a strikeout on a pitch that initially appeared to be more than a bit low, especially against 5-foot-9 Rays prospect Vidal Brujan. Yet, after a brief pause, home plate umpire Erich Bacchus reared back and rang up Brujan, who stared at Bacchus, dumbfounded.

Except that in this case Bacchus was merely the messenger. The real call was made by a computer, sent to an iPod clipped to his belt, then relayed to an ear piece before Bacchus relayed the call.





The automated strike zone was in effect for every game played at Salt River Fields, which is the home of the AFL’s Salt River and Scottsdale clubs. Major League Baseball was testing the TrackMan technology in a more casual setting.

And Brujan’s strikeout, which left Lynch laughing on the mound, wasn’t a one-time bug. Hitters throughout the brief AFL season were getting rung up on pitches catchers were scooping out of the dirt as well as ones that crossed somewhere near the middle of a hitter’s chest.

By the end, two things were clear: Pitchers with arsenals geared toward working from the top to the bottom of the strike zone were at a stark advantage, and nobody—neither hitters nor pitchers—was happy with TrackMan.

"Not a fan,” Angels outfielder Brandon Marsh said. "Just because the ball can barely clip the zone—top, bottom, inside, outside—and the catcher can have his wrist break and drop the ball and it’s still a strike.

"I mean, I can’t complain against it, because it’s the ‘perfect’ strike zone, but baseball has always had human error in it, good and bad. I feel like, if you take that away from the game it’s changing the whole game. I’ll adapt to anything whether it happens.”

For a quick refresher on what TrackMan has been tasked with enforcing, we turn to the MLB rulebook, which defines the strike zone as “that area over home plate which is a horizontal line at the midpoint between the top of the shoulders and the top of the uniform pants, and the lower level is a line at the hollow beneath the kneecap.”

With that in mind, a pitch gets called a strike when “any part of the ball passes through any part of the strike zone.”

That last part is the key. If a small piece of the baseball passes through a small piece of the strike zone, that’s a “rulebook” strike. As seen in the AFL, calling a game strictly by the book makes it clear that the strike zone is far bigger than human umpires normally enforce.

Even with the built-in advantage created by TrackMan, pitchers in the AFL were not impressed with what they saw during their games at Salt River Fields.

“Whether it benefits me or not, I’m just coming at it from a baseball purist standpoint. Umpires are back there and they have a job for a reason,” Mariners righthander Penn Murfee said. “It’s to manage the calling of the game—why take out one of the biggest pieces of that? The enemy of good is better in a lot of senses and I just think that’s a good idea from someone who came along who never should have been tempted.”

Besides the zone itself, another factor that irked both hitters and pitchers alike is the delay between the pitch hitting the catcher’s glove and when the home plate umpire relayed TrackMan’s decision. The entire process took roughly four seconds, and led to hitters getting punched out to end innings as the catcher was throwing the ball back to the mound in preparation for the next pitch.

“I think the weirdest part is just the pause from the pitch hitting the catcher’s glove and then the umpire calling it a strike,”Rays outfielder Josh Lowe said. “Sometimes it happens throughout the regular season where an umpire is frozen on a pitch and it takes him a second or two to call it, but you see it more out here, where you don’t know if it’s going to be a strike or not.”

Those familiar with umpires like Tim McClelland and Joe Brinkman are used to not seeing the visualization of the strike call until very late after the pitch is in the catcher’s mitt, but those guys vocalized the call for the hitter and pitcher much earlier, so not everybody was left in the lurch. The human behind the plate during TrackMan games was forced to wait, just the same as everybody else, which can obviously annoy all those involved.

For all its faults that still need to be corrected, there are some obvious advantages to the TrackMan zone. First, clearly, is consistency. Teams need not worry about whether an umpire’s zone typically favors hitters or pitchers, or whether an argument in the third inning might influence a call in the seventh inning. So long as everything runs smoothly, the strike zone will be the same from the first inning until the last inning.

And for as weird as the strike zone has seemed at its highest and lowest points, the outside and inside corners are going to be called consistently and correctly. In other words, balls cannot be turned into strikes by skilled catchers with quick hands and smooth actions.

There’s also the benefit to pitchers with poor in-zone command. If a catcher sets up for an outside fastball, for example, but a the pitch is yanked onto the inner part of the plate, human umpires might be fooled enough by the catcher reaching for the pitch to call it ball.

That’s not the case with TrackMan.

“It does allow the pitchers to be able to throw fastballs at the top of the zone, competitive pitches, and for those pitchers to get those called strikes that are well deserved on their end,” Angels outfielder Jo Adell said. “For hitters, obviously, that’s a tough pitch to hit. There’s a lot of low-ball hitters these days, and it’s a way for pitchers to be effective at the same time. How good it is inside-outside really helps the hitters not feel like they have to get up to bat with a fungo sometimes.”

Even with the benefits they reaped, both hitters and pitchers who experienced the TrackMan zone in the AFL came away still wanting a human umpire behind the plate, like they had during the regular season and at games at the AFL’s other three ballparks.

“I think I’d rather deal with a human error rather than a computer error. It’s still really tough to get this zone adjusted to everything,” Lowe said. “Like I said, the top and bottom of the zone is the hardest part, and if they’re ever going to use that in the big leagues or any other levels, they’re going to have to work on that. But for the most part I’d rather deal with a human umpire.”

Mariners lefthander Raymond Kerr had similar feelings toward the zone he faced during games at Salt River compared with his experiences in the rest of his games.

“I don’t like that. It takes away the catcher’s ability to frame, and umpires are delayed on calls. I just think it slows down the game a little bit,” he said. “I heard about it like two months ago, but I didn’t think they were really going to do it, because the umpire doesn’t really have a job after that. They’re just sitting back there getting buzzed calling strikes and balls. I think by doing that you’re going to make umpires a little lazier behind the dish.”