Meet Detroit Tigers' Sean Guenther, the unsung hero of bullpen success in playoff push

The Detroit Tigers — three months before the famous Tyler Holton waiver claim — picked up then-injured left-handed reliever Sean Guenther off waivers from the Miami Marlins in November 2022.

He represented the third player claimed off waivers in the tenure of president of baseball operations Scott Harris .

Twenty-two months later, Guenther emerged as the unsung hero of the Tigers' bullpen throughout an improbable postseason push. He specializes in matchups against left-handed hitters while holding his own against right-handed hitters.

"I can't remember a time I had this much fun playing this game," Guenther said. "It's fun in the clubhouse, it's fun on the field, it's fun traveling. We're playing well, we're doing well, and we're having a good time doing it. You can't really ask for much more at your job. It's awesome."

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Guenther, 28, recalled the day he joined the Tigers.

He was in Jupiter, Florida, where he lives during the offseason. He went to a Florida Panthers game with his Marlins teammates, which is when he received a call from the Marlins explaining he had been placed on waivers and claimed by the Tigers .

Five minutes later, Tigers assistant general manager Sam Menzin called Guenther to introduce him to a new organization.

"It was a good conversation," Guenther said.

Guenther, who made his MLB debut for the Marlins in 2021, underwent Tommy John surgery in April 2022 to repair the ulnar collateral ligament in his left elbow. It had been seven months since the surgery when the Tigers claimed him off waivers. He didn't pitch in a competitive game until May 2023.

In 2024, Guenther has a 0.90 ERA with two walks and 11 strikeouts across 20 innings in 16 relief appearances, including one run over 18⅔ innings in 15 games since his Aug. 22 promotion from Triple-A Toledo.

His 0.48 ERA ranks No. 1 among 14 pitchers from the Tigers with at least five innings since Aug. 22.

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"It really just means the world, honestly," Guenther said. "Those two years between surgery and everything, every day you're going to work and doing the most monotonous, repetitive stuff, and you think about situations like this. You're like, 'Hey, if I do this right and put in the time and put in the hours, I can get back to this level and be playing meaningful baseball in September.' It's more than you can even really dream about."

Guenther has inherited one runner in four of his last six games.

He hasn't allowed any of them to score.

His toughest task was Sept. 18 against the Kansas City Royals, entering in the eighth inning to protect a two-run lead with a runner on first base and nobody out. He induced a ground-ball double play with a second-pitch sinker, setting the tone for his scoreless inning.

The Tigers won, 4-2 .

"He's very durable, but mostly, it's movement and strikes," manager A.J. Hinch said. "He's unafraid of using his best stuff. I think he's a great example of development continuing, as he even got a taste of the big leagues a couple of years ago."

Guenther benefits from an elite 63.6% ground-ball rate, far above the 44.4% league average. But he also benefits from pinpoint command of his sinker, changeup and slider. He doesn't generate many strikeouts, but rarely issues walks.

A 90 mph sinker has been the biggest reason for his success.

He didn't throw a sinker before joining the Tigers.

Guenther doesn't know who prescribed the sinker (maybe it was Harris), but he was told by director of pitching Gabe Ribas to start throwing the sinker when he reported to the Tigers' spring training facility to continue his rehab from Tommy John surgery.

"That's a huge help for me," said Guenther, who practically scrapped his four-seam fastball. "It can get guys out early counts, it can force weak contact."

The Tigers also instructed Guenther to increase the usage of his changeup, from 8.9% in 2021 to 31.2% in 2024. The new changeup profiles like a splitter.

"It's a little different from the one I was throwing previously," Guenter said, providing another example of the Tigers' pitching genius , "but in 2021, I was throwing that pitch less than 10% of the time. It was a non-factor. Now, it's a real weapon for me."

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Guenther enjoys watching "Ted Lasso," a sports comedy TV show that airs on Apple TV+. He keeps episodes of his favorite show downloaded to watch when he has free time. He also lives by a Lasso-inspired sticker on his water bottle.

The sticker: BELIEVE .

"I'm a big believer in speaking things into existence and visualizing things before they happen," Guenther said. "Showing up to the yard, the expectation to win is huge for us, and I think it's clubhouse wide. When you have everyone pulling in that same direction, you can really get going — like we are."

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After an impressive road trip, the Tigers returned home to Comerica Park for a six-game homestead to finish the season and solidify their spot in the postseason.

Guenther earned a standing ovation from the fans in Wednesday's 7-1 win over the Tampa Bay Rays after throwing two perfect innings with three strikeouts.

He has never received cheers like that before.

"That was pretty sweet," Guenther said. "Honestly, I didn't realize it was happening. I always kind of stare at the ground when I walk off, but I don't know why. I heard something was going on, so I looked up and saw. It was really cool."

Two years ago, Guenther was designated for assignment by the Marlins while recovering from surgery. Two months ago, he was working hard in Toledo in hopes of his first MLB opportunity since 2021.

Now he's likely headed to the postseason, where there could be more standing ovations.

"Yeah, I hope," Guenther said.

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

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This article originally appeared on Detroit Free Press: Meet Detroit Tigers' Sean Guenther, the unsung hero of bullpen success in playoff push