An 88 mph knuckleball?! Tigers farmhand has one -- and just got promoted

June 10th, 2025

This story was excerpted from Jason Beck’s Tigers Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

The pitch from Kenny Serwa seemingly floated in the air as Victor Bericoto swung and missed for strike three. Just as Bericoto whiffed, so too did Erie SeaWolves catcher Eduardo Valencia, fooled by the sudden, late movement as it skipped off his glove and into the dirt. While Valencia retrieved the ball, Bericoto looked to the ground and shouted in disgust on his way back to the dugout.

That’s how Serwa can tell if his knuckleball is working.

“If [the catcher] isn’t catching them,” he said a couple days earlier, “then it’s usually doing what it’s supposed to.”

Four pitches later, Turner Hill – a tenacious hitter with more walks than strikeouts for his pro career – was left shaking his head and glancing back to the mound after fanning on another Serwa knuckler.

This is what the knuckleball can do to hitters. For Serwa, it turned his Double-A debut last Thursday at UPMC Park into an introduction for several Richmond Flying Squirrels to his bread-and-butter pitch. He fanned four in a five-batter span from the third inning into the fourth. He then allowed a two-out walk and a ground-ball single, hit a batter, then gave up a two-run single on a fastball.

COMPLETE TIGERS PROSPECT COVERAGE

Serwa finished his Double-A debut with six innings and a victory, allowing four runs on four hits with two walks and four strikeouts. It was an impressive debut for a pitcher making his 11th appearance and sixth start in Minor League ball, the latest stop in a journey that included four colleges and two indy ball teams, most recently the Chicago Dogs last summer.

“The most fun part of this whole experience? Honestly, all of it together,” Serwa said. “I worked so hard to finally get to affiliate ball, and I’m just soaking everything in, all the information, all the technology and everything that they have here in the Detroit organization. I’ve never had access to anything like it. The coordinators and everybody are always so helpful and trying to help make you better.”

The Tigers have not had a full-time knuckleballer on their staff since Steve Sparks, whose four years in Detroit included a team-leading 14 wins in 2001. Eddie Bonine, who went between the Tigers’ rotation and bullpen from 2008-10, threw a knuckleball, but not as his primary pitch.

Knuckleballers have become a rarity around pro ball. Between pitch design, the quest for velocity and the chase for spin, the pitch doesn’t really fit into modern pitching instruction. But with teams looking to build staffs with pitchers bringing different arm angles and pitch looks, it has a place.

Considering the unique pitchers the Tigers have acquired in recent years, it makes sense that they took a shot on Serwa, signing him in January after he worked out at Tread Athletics in Charlotte. His work there included a now-viral YouTube video showing an 88 mph knuckleball, the fastest ever recorded.

“I have been thinking my entire life that the game needs another knuckleballer,” Serwa said. “I’ve always felt like I am the next knuckleballer and just waiting for the opportunity to show that I am. I’ll keep mixing up the speeds and getting the movement nasty and keep working on it, everything like that. And I hope to be up there someday soon.”

The journey there is unique, and not just for all the stops. He’s a 27-year-old grad school product with a family in a farm system loaded with young talent. He’s also throwing an inherently unpredictable pitch at a time when pitchers use technology to try to know what their pitches will do when executed well.

“Last week, [catcher] Bennett [Lee] was struggling with it. The ball was moving all over the place, it was crazy,” High-A West Michigan manager Tony Cappuccilli said. “I’ve never seen his knuckleball move that much. And we were telling Bennett to just knock it down. We had fun with it.”

Serwa throws two variations of the knuckleball, a pitch he learned from his dad as a kid. In addition to the higher-velocity version, there’s the slower, sharper-moving version, nicknamed the Yoshi for the Mario Super Sluggers character, who boasts the quirky offspeed pitch.

Serwa also has a low to mid-90s fastball and a traditional curveball. But the Tigers want him to work the knuckleball as much as he can.

“It’s always there,” Serwa said. “I can usually find a feel for it.”

So far, so good. He’s 4-1 with a 3.21 ERA between the Whitecaps and SeaWolves, striking out 38 batters over 42 innings. With just 10 walks, he hasn’t battled control too much. And with 32 hits allowed -- including just one home run -- he hasn’t been pounded.

“He’s done a great job being able to limit walks and use the knuckleball as a weapon to get ground balls and soft contact,” Cappuccilli said.