MILWAUKEE — Ryan Braun certainly doesn’t fit the image fans conjure up when they hear that a baseball slugger has been accused of using performance-enhancing drugs.

Since he joined the Milwaukee Brewers in 2007, Braun has belted big home runs not with cartoonishly large muscles, but with a sweet swing and an ultra-quick bat. Last season, he helped drive the Brewers to the playoffs and was voted the NL’s Most Valuable Player.

Now Braun finds himself fighting a 50-game suspension after news leaked that he has tested positive for a banned substance. He steadfastly maintains his innocence.

A spokesman for Braun said in a statement issued to ESPN and The Associated Press that there are “highly unusual circumstances surrounding this case which will support Ryan’s complete innocence.”

ESPN cited two sources Saturday in first reporting the result, saying Braun tested positive for elevated levels of testosterone, adding that a later test by the World Anti-Doping Agency lab in Montreal determined the testosterone was synthetic. Braun is appealing, according to people familiar with the case.

And fans may be inclined to believe Braun, given his clean-cut image and that he hasn’t tested positive or even been suspected of using banned substances in the past. And, perhaps above all, the fact that he doesn’t look like a human science experiment.

But there is a long history of athletes accused of taking banned drugs insisting they did so to recover from injuries. Sports medicine experts acknowledge the drugs may help, raising the possibility Braun might have been doing just that.

Norman Fost, a professor of pediatrics and director of the bioethics program at the University of Wisconsin, said vigorous exercise breaks down microscopic muscle fibers.

“One theory is that anabolic steroids hasten the repair of those muscle fibers, and allow you to work out harder,” Fost said.

Dr. Susannah Briskin, a primary care sports medicine physician with Rainbow Babies and Children’s Hospital in Cleveland, says the potential injury recovery benefits associated with anabolic steroids have been tested on a limited basis but only on animals.

“This stuff will never end up being studied with humans,” Briskin said. “Any medical study must start with, `Do no harm.’ The problem is, there’s been a lot of harm proven in studying anabolic steroids.”

According to a document on the Mayo Clinic’s website, the potential injury recovery benefits of performance-enhancing drugs are part of their appeal to athletes.

“Besides making muscles bigger, anabolic steroids may help athletes recover from a hard workout more quickly by reducing the muscle damage that occurs during the session,” the document says. “This enables athletes to workout harder and more frequently without overtraining. In addition, some athletes may like the aggressive feelings they get when they take the drugs.”

Braun has dealt with nagging injuries in recent years, and other players have acknowledged they used performance enhancers to help them recover from injury.