MINNEAPOLIS -- Mike Pelfrey doesn’t mind stirring the pot on occasion. That’s what he had in mind when he called teammate Jordan Zimmermann following a friendly wager the two had placed on an NCAA tournament game during spring training.

Zimmermann had taken the top-ranked University of Virginia, Pelfrey had underdog Syracuse, and so when Virginia blew a 16-point lead and Syracuse pulled off the improbable upset to advance to the Final Four, Pelfrey made sure to ring Zimmermann as quickly as possible, just to get a gauge on how bad he was smarting over the loss.

“It was a complete meltdown,” Pelfrey said, laughing as he recalled the diatribe on the other end of the line. “He was cussing at me, screaming at me, fired up.”

When Pelfrey saw Zimmermann the next day, he was pacified, to a degree, but he was still pissed. The more Pelfrey gets to know his fellow pitcher, the less he is surprised by this reaction.

“That’s the way he gets. He's a competitor and I don’t think it matters if it’s a friendly game or he’s out there pitching,” Pelfrey said. “He wants to kick your butt.”

The relentless competitor that lies within the 29-year-old Wisconsin native has been evident even in his short tenure as a member of the Tigers. Zimmermann, who signed a five-year, $110 million deal with Detroit this November, has a start so superb that it is downright historic.

He went 24 1/3 innings before surrendering his first run with the Tigers, and even that one was under dubious circumstances. He has collected four wins and surrendered just three runs in his first four outings of the season, the best start any pitcher has had with the Tigers in franchise history.

His ERA heading into Saturday’s game against the Twins -- 0.35 – is mind-boggling. According to ESPN Stats and Info, only two other pitchers in the divisional era – Fernando Velanzuela and Roger Clemens -- have had a better single-season April ERA than Zimmermann.

Ask Zimmermann about that and he’s unlikely to offer anything more than a shrug. Self-promotion is not one exactly part of the Midwestern farm boy ethos and though he thrives in the spotlight, he certainly does not seek it. When he’s forced to talk about himself, the act elicits an almost pained grimace, so it’s not surprising he’s doing his best to downplay his early achievements.

“There was some luck involved,” Zimmermann told ESPN.com in a recent conversation. “I was in a bunch of jams and I was able to get out of ’em. It doesn’t always go like that. I know I’ll probably never have a stretch like that again. I’m gonna give up runs, I know that. It’s just limiting the runs. This stretch I had, I just got lucky on a few occasions.”

Though Zimmermann seems averse to accolades, those around him are more than happy to heap praise, especially considering how critical his steadiness has been. The first month has been pockmarked by some erratic performances from the Tigers pitching staff, and Zimmermann has provided the only real consistency they’ve gotten from their rotation regulars.

“When players see a guy like Zimm take the mound, they instantly feel good about their chances of winning the game,” manager Brad Ausmus said.

Zimmermann’s tenacity is arguably his biggest strength. He shows no fear. He attacks hitters. And he has unwavering confidence in his stuff.

“He’s all business. He gets on the mound and he’s not there smiling. He gets the ball goes in rapid fire, aggressive, boom-boom-boom, and that’s the way it is,” Pelfrey said.

Zimmermann’s efficiency has been a godsend for the Tigers’ position players, but it has also kept them on their toes. He pitches quickly, wasting no time in his delivery, and that has largely worked to his advantage.

“You’ll see hitters step out, call a timeout, try to break the rhythm of it, just because they want to get set. They want to get timing and be comfortable,” backup catcher Bobby Wilson said. “That's what working fast does -- it eliminates them being able to get comfortable, digging in -- they have to know as soon as they get in the box, he's starting his windup.”

His tenacity on the mound is probably his greatest strength. He doesn’t show fear. He attacks hitters. And he’s confident in his stuff. Those qualities have proved a lethal combination.

After being summoned from the minors in the wake of James McCann’s injury, Wilson was, in his first game as a Tiger, tasked with catching Zimmermann on the road against the Pittsburgh Pirates. It was an easy assignment and Wilson loved how he went after hitters.

That game wasn’t without trouble; rather, Zimmermann had to wriggle out of some tough spots, but it was the way he pitched when he was in a jam that was truly impressive. With the bases loaded and Zimmermann behind in the count 2-0 against Pittsburgh’s Gregory Polanco, Zimmermann got him to pop up on a backdoor slider. That showed guts, Wilson said.

“He wasn't going to give in to him and just groove him a fastball middle-middle. He was still pitching, even though the situation -- obviously you don’t want to make your nastiest pitch 2-0 with the bases loaded, but he wasn’t intimidated to do it,” Wilson said. “He got a strike and then got a fly out. And that's kind of what it boils down to. He's a bulldog and he wants to compete. He’s not scared or intimidated by anybody.”

When Zimmermann does make a mistake, he doesn’t dwell on it, either. He’s able to shake any gaffe quickly and re-calibrate -- a quality that has stood out to veteran second baseman Ian Kinsler.

“People talk about him working quickly and him having a bulldog mentality and trusting all his pitches or whatever, but it's what he does when he gets into trouble and how he reacts to tough situations, the way he’s able to react to that and get himself back into the right frame of mind quickly, [that’s] impressive,” Kinsler said. “He’s got a short memory. He’s able to get over it and refocus himself quickly and that’s huge in this game.”

As for his demeanor off the mound?

“He’s very sarcastic,” Kinsler said, a high compliment from one of the clubhouse's kings of sarcasm. “You rarely can get a full laugh out of him. He'll chuckle and stuff, but he seems to be a pretty serious guy on the exterior. On the interior, I don’t think he’s that serious.”

Pelfrey has chipped away enough at that tough exterior to see that latter part, joking that if didn’t make Zimmermann laugh, he never would.

“He’s real serious. He just kind of goes around and looks like he's a little bit angry. Everyone asks him that, are you mad?,” Pelfrey said of the first few weeks he was getting to know him.

Now he’s seeing evidence of what his former teammate Kurt Suzuki had told him about Zimmermann -- great guy, awesome teammate and “a king of the one-liners.”

“He’s hilarious. He's funny. When him and Pelfrey get together, it’s a good time,” Wilson said.

Opponents aren’t laughing though, and neither are the other suitors that missed out on him in free agency. Zimmermann said he signed with the Tigers because that was the team that showed the most sincere interest. Some teams were reluctant to ink him to a long-term deal because of concerns about his arm -- he is almost seven years removed from Tommy John surgery -- and several teams dipped their toes in but were clearly holding out to see where marquee names David Price, Zack Greinke and Johnny Cueto would go first.

Want to bet those teams are having second thoughts now?

Zimmermann smiles, but just barely.

“Hopefully that’s what they are thinking.”