BOSTON -- Al Reyes had an MRI exam on Friday in St. Petersburg, and the diagnosis is biceps tendinitis for the Rays right-hander.

"Nothing severe, nothing horrible," Rays manager Joe Maddon said. "He's going to go through the normal medication involvement and treatment starting Monday. It doesn't sound like anything severe or long. It's just that for now. We don't have a definitive timetable right now, but it doesn't seem to be one of those things that will take a whole lot of time either."

Reyes went on the 15-day disabled list April 16 and was scheduled to return to the team on Thursday, but just didn't quite feel right.

"Just [need to] get that irritation to subside," Maddon said. "Tendinitis is such an annoying kind of a thing. It just burns a little bit and you've got to get rid of it."

Reyes is 1-2 with a 9.00 ERA in seven appearances in 2008. He recorded a team-leading 26 saves in 2007.

When asked for a guess about when Reyes might return, Maddon said: "I'd say a couple of weeks would be reasonable at the most."