SEATTLE -- One of Tigers prospect Justyn-Henry Malloy’s best tools is strike-zone awareness. So he knew that the low-and-inside fastball thrown to him in a 3-1 count in the second inning of the SiriusXM All-Star Futures Game was incorrectly called a strike.

Malloy just didn’t immediately know what to do about it.

“Challenge! Challenge! Challenge!” his AL teammates said.

In that instant, Malloy went with his fellow players, tapped his helmet and asked for a review of home-plate umpire Macon Hammond’s call. With that, the automated ball-strike (ABS) challenge system went into effect. The location of the pitch, captured by Hawk-Eye cameras, was summoned, and the correct call was relayed by T-Mobile’s 5G Advanced Network Solutions:

Ball four.

So Malloy got his walk, even though AL manager Harold Reynolds, who was mic’d up for the Peacock broadcast, was playfully displeased.

“Man,” said Reynolds, “if that’s Ken Griffey Jr., and he called for that on a walk, I’d be like, ‘What’s wrong with you? I need a homer from you!’”

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The annual Futures Game exhibition is, as the title implies, a window into MLB’s future. For seven innings, some of the top prospects in the game get to showcase their skills in front of a wider audience than they have at their pipeline pit stops.

But this year’s Futures Game also utilized an experimental rule change that, like the players themselves, has the potential to be a part of MLB’s future.

For the uninitiated, the ABS challenge system is a compromise between full ABS -- or so-called robot umps -- and tradition, with a sprinkle of strategy tossed in. In full ABS, all ball-and-strike calls are made by the Hawk-Eye system and instantaneously relayed to the home-plate umpire. In the ABS challenge system, the ump calls balls and strikes as usual. The wrinkle is that teams have a limited number of balls and strikes they can ask to be reviewed by Hawk-Eye in a given game. (Here is a more complete explanation of the ABS challenge system.)

That’s where the strategy comes in: You don’t want to blow your challenges at inopportune times and not have any at your disposal in a late or clutch situation.

At the Triple-A level this season, MLB has experimented with both versions of ABS. Each week, teams play six games against a single opponent -- three of the games are with full ABS and three are with the challenge system.

With MLB having just implemented dynamic rule changes in 2023 (the pitch timer, bigger bases and defensive shift limits) and with the operational components of ABS still being thoroughly tested in the Minors, Commissioner Rob Manfred said it is unlikely ABS will reach the bigs in 2024.

But the challenge system’s use in the Futures Game was a pretty clear example of how seriously the league is testing the system.

“It's a really unique way to put the game back in the players' hands,” said Raúl Ibañez, the senior vice president of on-field operations for MLB and the skipper for the NL squad in the Futures Game. “It's really designed to correct the kind of egregious calls, where a player has the opportunity to challenge a call and keep it if he wins. But it's also a cool team dynamic the way that teams seem to use 'em strategically and spread them out.”

The Futures Game was a window into how the ABS challenge system works … and also, it wasn’t. At Triple-A and in the Florida State League, where the ABS challenge system is also in place this season, teams have three challenges per game. If their challenge is successful, they get to keep it.

Because the Futures Game was only seven innings and a non-binding exhibition, each team was limited to just two challenges -- with no retention for successful challenges.

That’s why Reynolds acted so aghast when Malloy challenged that 3-1 pitch for a second-inning walk. It was his team’s second of two challenges … in the second inning.

“Two innings, and we were done!” Reynolds said after the game, shaking his head and smiling.

In the top of the inning, Reynolds’ catcher, Mariners prospect Harry Ford, had wasted the AL team’s other challenge by asking for a review of a relatively meaningless 2-1 pitch that was called (and confirmed as) a ball.

“Hey, I wanna play around with it, you know?” Ford said. “I never got to use it before.”

Ford, who was new to the system, did not appear to realize his team only had two challenges -- and Malloy, who was familiar with it as a member of the Triple-A Toledo Mud Hens, did not know that, for this particular game, successful challenges were not retained. So forgive them their impetuousness.

The NL team was more patient with its use of challenges, but it whiffed on both of them. In the sixth inning, Justin Crawford unsuccessfully challenged a 1-2 fastball that just barely nicked the bottom of the zone. The very next batter, Victor Scott II, unsuccessfully challenged a 3-2 breaking ball that just barely nicked the top of the zone. In both cases, Hammond’s work behind home plate was vindicated, and viewers, perhaps, had a better appreciation for how difficult the job of an umpire is.

“The umpire’s back there trying to see someone’s fastball, and it’s 102 [mph] with two-seam [sinking movement],” Orioles outfield prospect Heston Kjerstad said. “They’re not going to be perfect. This is a built-in system to help them out. Some of the umpires even told me they like it because sometimes they favor an inside or outside part of the plate, and it lets them know [if they’re right or wrong] if someone reviews it. It’s really interesting. I think it’s for the better.”

After the Futures Game, a fan walking in a hallway at T-Mobile was overhead to say, “That challenge system they were using is wild!” This game was as good a place as any to familiarize fans with a system that, while not unlike what has been used in professional tennis for many years, is obviously new to baseball.

Players and staff have generally been positive in their assessment of the challenge system, but getting the zone right is of obvious importance. This year, the ABS strike zone was adjusted from 19 inches wide to 17 inches wide (the same as home plate), and it was also lowered slightly.

“I do agree with the fact that the edges are a little tighter,” Mets prospect Mike Vasil said. “Last year, in the Florida State League, the 19 inches we were getting, I was getting some calls that I wasn’t even getting in the ACC [in college], so that was a little funky.”

The evaluations will continue. And perhaps one day, much like these prominent prospects, the ABS challenge system will get the call.

“Major League Baseball's not going to roll out rules unless they know it's going to be successful,” Reynolds said. “We look at this year, with the rule changes and everything that's happening. That's 8,000 games they tested in the Minors before they rolled it out. Because if you don't do it right, you only get one shot at it.”