ESPN Mixed Martial Arts

BROOKLYN CENTER, Minn. -- In the lobby of the Minnesota Martial Arts Academy, where Sean "The Muscle Shark" Sherk has trained for 14 years, a shrine to the former UFC champ greets all visitors. On the wall, there are magazine posters showing him with the UFC lightweight belt dangling over his shoulders and promotional posters from his past championship bouts.

But just a few days ago, Sherk checked his MySpace page and found a note from a friend who wanted to know when he was going to fight again.

For the first time in a long time, Sherk's not a headliner. And he's not happy about it.

He's on the undercard of Saturday's UFC 90, where he'll face Tyson Griffin -- one of the UFC's top young 155-pounders -- in one of the more important fights of his career. Five months ago, current lightweight champ B.J. Penn stopped him in the third round of their highly anticipated bout in May via TKO.

The UFC stripped Sherk of his title before that fight because he tested positive for steroids after his first lightweight title defense against Hermes Franca in July 2007, prompting a one-year suspension by the California State Athletic Commission. Sherk denied that he used steroids and fought the suspension, which was eventually reduced to six months, but he still hasn't removed the stain it placed on his career.

Sherk calls his upcoming fight against Griffin "a must-must win" that could get help him back to the top of the division.

"For me, you know, this fight is about getting my career back on track," Sherk said. "It got derailed after the Franca fight, and then I lost my last fight to B.J. So the last year … I've been struggling a lot. I want to get the career back on track, get things back to where they should be. A win over this guy will put me right back in title contention again."

A loss against Griffin, who has only one defeat in 13 fights, could put Sherk in Chuck Liddell/Wanderlei Silva/Mirko "Cro Cop" Filipovic territory and make him a former champ without a ton of options going forward. A win puts him right back in the mix in the lightweight division. Right now, Kenny Florian will probably become the No. 1 contender for a title shot against Penn with a win over Joe Stevenson next month. But Sherk earned a convincing victory over him in 2006 to win the lightweight crown.

Sherk believes Griffin has the skills to become a world champion, but he'd like to get a win over him before he does, as he pursues his goal of becoming a two-time lightweight champion.

"My overall goal is to win that belt again," said the 35-year-old Sherk. "There's a very small group of individuals that can say they're two-time UFC world champions. I want to be one of those individuals. I think that'll secure my place in the UFC Hall of Fame."

For now, Penn will hold off on defending his title to take a super fight against Georges St. Pierre at 170 pounds in 2009, but Sherk's still hoping for an eventual rematch.

First he'll have to get through a tough fighter in Griffin, who matches up well with Sherk. They're both strong wrestlers who haven't lost many fights. And both are known for their explosive takedowns and ground and pound.

Griffin's career could get a huge boost if he beats a former champion like Sherk. The Xtreme Couture fighter is one of the UFC's top lightweight prospects; his explosive fighting style also makes him one of the entity's more exciting up-and-coming contenders.

"I think it's a very important fight," Griffin said. "The fact of the matter is, every fight is the most important fight in your career in the UFC because you gotta win to keep a job. But definitely fighting a guy with the name of Sean Sherk is very important for my name in MMA and my ranking in the world, so to speak. And it will push me toward the top of maybe getting a title shot one day."

Sherk's impressed, and sees a younger version of himself in the 24-year-old Griffin, but he doesn't think Griffin has the résumé to compete with him.

"Stylistically, I think we're a lot the same," Sherk said. "Obviously, physically, we look a lot the same. I see a lot of same attributes in myself that he has as well. To be honest with you, I just don't think he's seasoned enough yet. We're talking about a guy with 13 fights who hasn't fought an A-level fighter yet, versus a guy who's got 40 fights who's been fighting A-level fighters for six years. So there's a lot of experience coming into this that I have."

Myron P. Medcalf is a staff writer for the Star Tribune in Minneapolis and a freelancer for ESPN.com and ESPN The Magazine.