LAKELAND, Fla. — Detroit Tigers right-hander Wilmer Flores, a prospect who could make his MLB debut this season but still needs a taste of Triple-A Toledo, fired a 99.9 mph four-seam fastball in his first spring training game.

His fastball averaged just 92.9 mph last season.

"I'm trying to get back to what I used to be, a power pitcher," said Flores, whom the Tigers added to the 40-man roster in November 2023. "We're getting there. That was my offseason focus, trying to get back to that fastball."

Flores, 23, allowed four runs on four hits while recording just two outs in the eighth inning Sunday against the Tampa Bay Rays, his first appearance of spring training.

The 54.00 ERA looks terrible.

MORE ABOUT HIM: Tigers' Wilmer Flores, brother of MLB veteran, has 'some of the nastiest stuff'

But the underlying data reveals a new-and-improved version of Flores on the mound. He boosted the metrics of his pitches by moving his body faster throughout his delivery, as requested by pitching coach Chris Fetter and assistant pitching coaches Robin Lund and Juan Nieves.

Manager A.J. Hinch explained the reasoning.

"His body is moving faster," Hinch said, "which is something our pitching group always talks about with pitchers, whether young or old. ... A lot of guys will go to the scoreboard and see velocity. We need to figure out why that happens. If you study Wilmer when he's throwing hard and when he's not, it's about how fast his body is moving, meaning his torso or some of his torque, all things that are way above my expertise, but luckily, we have Fett and Robin and Juan to dissect all of that."

Optimizing the movement of his body was Flores' offseason assignment from the Tigers.

"The most important thing is to improve my stuff," Flores said. "If my fastball is better, my other pitches are going to be better. ... I was working to get stronger with a power build. I lost some weight to get to that point. I'm just starting to move faster and move better."

[ MUST LISTEN: Make "Days of Roar" your go-to Detroit Tigers podcast, available anywhere you listen to podcasts (Apple, Spotify) ]

Flores threw 22 pitches against the Rays: 12 four-seam fastballs, four sliders and six curveballs. Here's a look at each of those pitches in his first spring training appearance:

• Four-seam fastball: Flores averaged 98.4 mph and maxed out at 99.9 mph, up from an average of 92.9 mph and max of 97.1 mph last season. He added four more inches of induced vertical break, from 12.2 to 16.2, meaning his fastball is getting more ride in spring training.

• Slider: Flores averaged 88.3 mph, up from an average of 84.2 mph last season.

• Curveball: Flores averaged 81.4 mph, up from an average of 78.6 mph last season. His curveball is traveling on a straighter path with more topspin in spring training.

Flores, who also throws a below-average changeup, didn't try to throw any of his pitches with more velocity. More velocity was simply the result of the changes to his body movements. He also didn't intentionally raise his arm slot, but he is throwing from a higher arm slot than last season.

It's a fascinating development.

"It's about getting in the right position just before throwing," Flores said, "and that makes me go over the top. I think it's helping. The curveball numbers are even better than last year, so I think it helps the curveball. I'm just trying to move good."

UTILITY PLAYER: Don't forget about Andy Ibáñez. He is 'ready to play' wherever Tigers need him

The results, though, need to be better.

Facing the Rays, Flores recorded back-to-back outs before he completely fell apart. He gave up hits to four batters in a row — single, double, double, double — before Hinch pulled him out of the game.

Hinch diagnosed the problem.

"He now has to figure out how to land some secondary pitches in the zone as he increases his velocity on his fastball," Hinch said. "But I was impressed by him tackling that and taking it into the game. There was a lot to like about Wilmer's outing. I know it doesn't feel that way in a box score, but I thought it was really, really encouraging."

Flores is aware of the next step in his development.

"Execution and controlling the counts," he said. "I need to attack the hitter. Don't fall behind in counts, be ahead in counts."

ANOTHER ARM: Tigers' Alex Faedo absolutely had to learn new changeup. Will it keep him in MLB?

Flores posted a 4.65 ERA with 33 walks and 90 strikeouts over 89 innings in 21 starts last season, including a 3.90 ERA in 18 starts for Double-A Erie. He also had a 4.00 ERA with four walks and 22 strikeouts across 18 innings in the Arizona Fall League.

If Flores develops within his new delivery, it won't be long before he makes an impact at the highest level. Imagine a 100 mph fastball — like the one he threw against the Rays in spring training — coming out of the Tigers' bullpen during a late-season postseason push.

"It was 99.9," he said.

Doesn't that round up to 100?

"It doesn't count," he said.

The easiest pathway for Flores to join the Tigers this season, considering the depth in the starting rotation, is as a relief pitcher with high-leverage upside, but before that happens, he needs to pitch in Triple-A Toledo.

Flores is expected to be a starter in Triple-A Toledo while the Tigers evaluate the best timeline for his arrival.

Maybe he will hit 100 mph in his next appearance this spring.

"We'll see," Flores said. "I'm just trying to throw strikes."

Listen to our weekly Tigers show "Days of Roar" every Monday afternoon on demand at freep.com, Apple Podcasts, Spotify or wherever you listen to podcasts. And catch all of our podcasts and daily voice briefing at freep.com/podcasts.

Contact Evan Petzold at epetzold@freepress.com or follow him @EvanPetzold.

This article originally appeared on Detroit Free Press: Detroit Tigers prospect Wilmer Flores seeks to be power pitcher again