The surprising Orioles have emerged as a fourth team with interest in free-agent pitcher Roy Oswalt, sources tell CBSSports.com.

The Orioles are joined in the mix by what could be a final four that includes the Red Sox, Phillies and Rangers. It isn't known if any additional teams are involved.

Oswalt, the former Astros and Phillies star, is said to want to be on a big-league mound by about June 15, meaning he's expected to select a team soon.

The Orioles said recently they'd like to bolster their pitching staff, and this certainly would be one way to do it. He was 9-10 with a 3.69 ERA for the Phillies last year.

Oswalt preferred the Rangers and Cardinals this winter when he turned down offers from at least the Red Sox and Tigers. Oswalt also is interested in pitching for a team with a chance to play in the World Series. The Orioles currently lead the American League East by one game. Phillies star Cliff Lee said Wednesday night he knows Oswalt wants to pitch, but hadn't heard where he might go.

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