Detroit Tigers left-hander Joey Wentz wishes he would have realized what was happening during last season's struggles, rather than after the season — when it was too late.

The 26-year-old had a 6.90 ERA across 105⅔ innings and made 19 starts in his 25 appearances. Hitters were hammering his fastball with a .374 batting average and .682 slugging percentage, but he couldn't figure out why.

"I don't think I was consciously aware of it as much as I probably should have been," Wentz said. "I didn't really think about it too much. I just tried to pitch."

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Wentz found the fix in his arm slot, but he isn't in the mix as a starting pitcher anymore.

The Tigers are stacked with MLB-ready veteran starters, so their younger potential starters — such as Beau Brieske and Alex Faedo — are caught in the limbo between starting and relieving at this point in spring training. Later on, the Tigers will decide whether those pitchers, among others, will join Triple-A Toledo's rotation or Detroit's bullpen. But Wentz, who has been a starter for his entire career, isn't in that group.

Instead, the Tigers moved Wentz to bullpen at the beginning of spring training because he doesn't have any minor-league options remaining — he would need to be removed from the 40-man roster and clear waivers before he could be sent to Triple-A Toledo. Essentially, Wentz needs to make the Opening Day roster as a reliever to guarantee he stays in the Tigers' organization.

"We have to make a real decision on him by the end of camp," Tigers manager A.J. Hinch said. "He absolutely can be an effective pitcher at this level. He's shown that in flashes. ... We're going to transition him to more of a bridge role and give him the best chance to make our team out of the bullpen. He's not in the starter competition."

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Wentz has started 26 of his 32 appearances over parts of two seasons in his MLB career, posting a 5.99 ERA with 60 walks (9.6% walk rate) and 125 strikeouts (19.9% strikeout rate) across 138⅓ innings.

His four-seam fastball was one of the worst pitches in baseball in 2023, with a minus-23 run value.

Back in 2022, Wentz's fastball performed significantly better in a solid seven-start cameo to finish the season. Opponents hit .209 with a .343 slugging percentage in 2022, 165 and 339 points off his 2023 results.

"Progressively throughout the year, my arm slot lowered and lowered," Wentz said. "My fastball just wasn't playing the way it needs to play in the major leagues. When that happens, I think everything takes a hit, and that's what happened."

By the end of the season, Wentz had an idea that his lower-than-usual arm slot was negatively affecting his fastball. His release height decreased from 6.36 feet in 2022 to 6.16 feet in 2023.

The Tigers showed Wentz some videos of his arm slot after the season to confirm the primary reason for his fastball troubles. He spent the offseason repeating his delivery with his regular arm slot.

"I wasn't, like, discovering fire," Wentz said. "I think it was kind of obvious when you see video and see that sort of stuff. It just takes conscious work, and you try to repattern."

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Now that Wentz has transitioned to the bullpen, the Tigers are curious to evaluate how he responds to pitching more often and if his raw pitches — fastball, cutter, changeup, curveball — become more effective in shorter appearances.

His fastball averaged 93.4 mph as a starter averaging more than four innings per game last season, but maybe Wentz's fastball will sit in the upper-90s when he empties the tank for two or three innings out of the bullpen.

He also needs to throw more strikes, thus keeping him away from hitter-friendly counts. If he avoids hitter-friendly counts, he can throw fewer fastballs and more secondary pitches.

"If he can improve strike throwing, improve the usage of his pitches," Hinch said, "where he has other things to go to when it's not a fastball-type request from the catcher, to me, it's the natural next step for him to be better."

Wentz is aware of his situation as an out-of-options player who struggled last season in a crowded room of starting pitchers, all of which were reasons for his transition to a long-relief role on the first day of spring training.

He hopes his fixed arm slot will help him find his way on the Opening Day roster.

"We have a really competitive team and a lot of good pitchers," Wentz said. "My focus is on throwing the ball well and making the team in any way that I can. I think I could help in a plethora of roles."

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

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This article originally appeared on Detroit Free Press: Detroit Tigers slot Joey Wentz into bullpen early in spring training