Jun. 13—MEMPHIS, Tenn. — During the seventh inning of a May 3 home start for Class AAA Memphis, Cardinals prospect Michael McGreevy thought for certain he caught the top of the strike zone while facing Marlins prospect Jacob Amaya.

Behind 2-0 in the count, McGreevy threw a sinker he saw cross the middle of the strike zone at the 5-foot-11 shortstop’s belly button. But the pitch was ball three.

So, the right-hander tried for the same spot again. The next sinker was slightly less elevated in the zone.

Ball four. “It’s like, ‘Where are these missing?’ You laugh about that because you feel like it’s a tin can,” McGreevy, one of the top strike throwers in the Cardinals’ system, said after a May 25 start of his experience with the automated ball-strike system being used across all of Triple-A. “But at certain times, like today, (catcher) Ivan (Herrera) was set up on the outside corner, and I definitely missed to the glove side and he totally yanked the glove just to try to catch it and keep it in front of him, and the umpire called it a strike. It’s give and take, for sure.”

Connor Thomas has seen the latter. “I’ve had Ivan set up on a fastball inside, and I’ve missed him, and he has to dive over the plate, and it like looks terrible, but it’s a strike,” said Thomas, a left-handed starter.

A season after all of minor-league baseball used the pitcher timer that debuted across Major League Baseball in 2023, all Triple-A affiliates this season have played games with the automated ball-strike calls and a pitch challenge system.

The ball-strike calls are “a bit tricky,” Herrera said in Spanish during an interview in Memphis. “I mean, the strike zone gets much smaller. It doesn’t count anything high for you.”

How it works Cardinals prospects in Class AAA were introduced to the system on April 25 while on the road against Durham. It previously was tested in Triple-A stadiums in 2022 and was used on opening day in the Pacific Coast League, according to a report by Baseball America. The set-up uses the Hawk-Eye tracking system to recognize balls and strikes, and the calls are relayed to the home plate umpire via an earpiece, the report noted.

With Triple-A teams typically playing a six-game series against the same opponent each week, the automated system is used in the first three games. Then a system that allows teams to challenge the home plate umpire’s called balls and strikes three times a game is used for the final three games of a six-game series. A team can retain a challenge if it gets a call overturned on the replay review.

“Honestly, I think it’s really good,” Cardinals shortstop prospect Masyn Winn said of the automated system. “I’m a little biased. I think it’s a little bit better for hitters, especially with the high fastball kind of being eliminated a little bit. I, personally, like it. I think it’s very consistent. I do like the challenge system a little bit more just because, I mean, there’s still that aspect of human error. The umpires back there, that’s their job back there. You put an electronic zone, and it kind of takes away the catcher’s job and the umpire’s jobs.”

Thomas has been on the opposite side of that.

“I will definitely say it’s hitter-friendly. Almost like extreme hitter-friendly,” Thomas said while seated in the Memphis dugout at AutoZone Park. “There is no more top of the zone, which you wouldn’t think affects me too much, but that’s part of my game. I’ve got to be able to pitch up in the zone for effect to keep them off of sitting on my low stuff. So when you take that away from any of us, it makes us extremely tight in a corner. We’re trying to battle.”

Pitcher Zack Thompson has, too. “Just picking and choosing where I can go up in the zone when I know guys are swinging because you’re not going to get the called strike up there,” the former Cardinals reliever and current Memphis starter said. “It’s a lot different. It’s going to take some adjustments on the player side and hopefully on the league side just to get that thing ironed out.”

On days when the automated system is used in Memphis, a visual of the strike zone and the spot it registers where the pitches are crossing the zone is shown on the left-field wall video board. That has led players to give a glance to see where the automated zone recognized a pitch.

In games in which the challenge system is in use, a strike zone on the video board is not available.

Challenges can be initiated by the pitcher on the mound, the catcher or the batter with the tap of the helmet or hat. The decision to challenge must be made immediately and, in the case of AutoZone Park in Memphis, the challenge review is displayed on the video board. That provices a similar visual to challenges seen in tennis matches on the ATP and WTA tours.

Waiting game Memphis players typically have refrained from using their three challenges in the early innings of a ballgame. As a team, they have tried to hold onto them until “high leverage” spots in the late innings when overturning a pitch might be more pivotal.

“I truly feel it’s another aspect of the game that you can win,” Memphis manager Ben Johnson said. “I want to win at every aspect in any way, shape or form that I can.”

The challenge can change an at-bat and a player’s discipline in the box.

“It helps you a little, too, to be more consistent in the strike zone,” outfield prospect Moises Gomez said in Spanish.

But from behind the plate, the new systems, particularly the automated ballstrike caller, could create changes in skills for catchers.

“There are catchers that have jobs because of framing,” Herrera said. “I think it’s going to create catchers that are less defensive and more offensive because ... you need a catcher that has good framing, that blocks, that throws, and there are lots of catchers that aren’t as offensive but are really good with framing, blocking.”