"League sources confirmed Tuesday evening that Detroit Lions defensive tackle Shaun Rogers, one of the NFL's most talented players at his position, has been suspended four games for a violation of the steroid and related substances policy.
The two-time Pro Bowl performer tested positive, sources said, for a product that Rogers used to help him control his weight. Those sources declined to specifically identify the substance, or to say when the positive test took place, but it is believed to have occurred either in the offseason or the preseason. "

http://sports.espn.go.com/nfl/news/story?id=2630061

I'm guessing it was Ephedra, the same thing punter Todd Sauerbrun was suspended for this year.