ANN ARBOR, Mich. -- Michigan lost some invaluable leadership on the offensive line when center David Molk graduated. A somewhat unlikely figure is volunteering to fill that void.

"I definitely see myself as a leader," junior left tackle Taylor Lewan told ESPN.com. "I want to be one of the main guys that really helps through all the successes and all the bad things. I want that to be put on myself.

"I'm the left tackle, the blind side. They made a movie about it. So it's my job to be a leader."

Lewan has been a lot of things during his career so far with the Wolverines. A standout lineman who's a key cog in the entire offense? Yes. A goofball who keeps his teammates laughing? Sure. A thorn under the skin of opposing players and occasionally officials? Yep.

But leadership is something new for Lewan, who's trying to shed some of his old labels for new and improved ones. Those who know him best noticed a major difference this spring.

"Taylor has just gotten more serious," said defensive lineman Craig Roh, who graduated from the same Scottsdale, Ariz., high school as Lewan. "For example, he's doing a diet now, and every Sunday he goes grocery shopping so he can make his own food. That may not seem like much, but for a college guy that's a lot. I just see him concentrating on things that matter more."

There's much at stake this year for Lewan. He'll be blocking for a potentially highly potent offense led by Denard Robinson and Fitz Toussaint as Michigan likely begins the season in the top 10. And a great year could have Lewan positioned to enter the 2012 NFL draft.

In his first 2013 Big Board, ESPN.com's Mel Kiper Jr. pegged Lewan as the No. 2 tackle and No. 12 prospect overall for next year's draft. Kiper said the 6-foot-8, 302-pounder "will get the Jake Long comparisons all year in Ann Arbor" and has "elite length and athleticism for the position."

Michigan offensive coordinator Al Borges agrees with that assessment.

"If Taylor works hard, stays concentrated and maintains focus, he can be very, very good," Borges said. "That's really his story. If he's focused, there isn't anything we ask him to do that he can't do."

Staying focused and disciplined has been a challenge at times. In his first two years of starting, Lewan has too often been a magnet for yellow flags. He cut down his penalties in the second half of last year but still drew three personal fouls, most famously getting tangled up with Michigan State's William Gholston several times before Gholston finally tried to punch Lewan, earning the Spartans' defensive end a one-game suspension.

He has also served as the team's resident comedian, cracking jokes and using his outgoing personality to keep things light. But Lewan says he has learned now when to have fun and when to get down to business.

"I think it's really a maturity thing," he said. "I'm 20 years old now, but I came into college when I was 17. I don't want to put it all on that or anything, but it's really just maturing.

"When I'm here in the building, football is No. 1. It's kind of one of those switches you have to turn on. I turn off all the joking."

Much of Michigan's fortunes may depend on the health of Robinson and Toussaint. Safeguarding them is a job Lewan takes very seriously.

"I'd rather be the guy who gets injured and plays with a broken wrist or something rather than them, because they're the ones running the ball," he said. "I can play with pain, but I don't want them to have to. Every part of my game needs to improve so that doesn't happen."

Lewan hasn't become a total killjoy. This spring, he bought a tandem bike that he could ride to practice, and teammates clamored to join him on it. The sight of the 300-pounder and another hulking football player on a bicycle built for two caused a lot of double-takes around campus.

"He's still Taylor," Roh said. "He's just not as much of a clown."

A focused Lewan could stake a claim as the best lineman in the Big Ten in 2012. And that's no joke.