According to a baseball source, the Tampa Bay Rays are one of “several teams” to express interest in former Red Sox reliever Manny Delcarmen, who became a free agent in December when the Colorado Rockies elected not to tender the right-hander a contract.

Delcarmen, who had emerged as a key reliever for the Sox in 2007 and 2008, struggled with injuries in 2009 and 2010 while watching his numbers get worse across the board. He posted a 4.99 ERA in 2010 (4.70 with the Red Sox, 6.48 with Colorado after being traded to the Rockies on Aug. 31 for Single-A starter Chris Balcom-Miller), and both his strikeout rate (6.5 per nine innings) and walk rate (5.5 per nine) were the worst of his career.

That said, he is young (28), and not far removed from being one of the top relievers in the AL East. In 2007-08, he had a 2.81 ERA in 117 appearances. The Sox believed that Delcarmen’s arm strength remained fine, and that his struggles in 2010 — which began in spring training — were due to a known mechanical issue.

“When he was good, he had the ability to get left and right-handers out, which was huge. It gives you that guy, kind of like an Oki, when he’s going good, who really makes your bullpen a little deeper. … He’s a local kid, who, he had times when he had some runs when he was pretty good. And there were some times when it didn’t go as planned. It’s not always perfect,” Sox manager Terry Francona said when Delcarmen was dealt. “When he would leave the rubber too quick, there were stretches where he just couldn’t get his arm to catch up on time. And he knew itbut he couldn’t make the adjustment during his outing. John Farrell would go out to the mound, and he’d say, ‘Yeah I know’. When everything was working on time, it worked good. But when it wasn’t, it took him a little while to make the adjustment.”

Delcarmen, who would not be eligible for free agency until after the 2012 season by the team that signs him, is now looking for “the right fit,” according to the source.

News of Tampa Bay’s interest first surfaced in a report by the St. Petersburg Times.