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07/10/08 8:47 PM ET

Wells to DL with strained hamstring

Jays outfielder injured during stolen-base attempt on Thursday

TORONTO -- The Blue Jays will have to take the good with the bad. On Thursday, Toronto learned that pitcher Dustin McGowan isn't likely to require surgery on his ailing right shoulder, but center fielder Vernon Wells will miss at least four to six weeks with a strained left hamstring.

The news regarding Wells was a blow to a Jays club that has struggled to mount much offense this season. Wells suffered a Grade 2 strain of the distal hamstring tendon while stealing third base in the sixth inning against the Orioles on Wednesday night, and he met with team doctors on Thursday to evaluate the extent of the injury.

"The only explanation that we have," Jays assistant general manager Bart Given said, "is that going to third, he kind of hyperextended his knee. When you hyperextend it, you put some strain on those tendons and he has some strain to it. It's not completely ruptured, which is good news."

Wells, who missed three weeks in June with a fractured left wrist, was placed on the 15-day disabled list on Thursday and he'll likely be sidelined until mid to late August. Wells -- signed to a seven-year deal worth $126 million prior to last season -- is hitting .287 with a team-leading nine homers and 42 RBIs in 64 games for the Jays this season.

With Wells out of the mix, the Blue Jays took the field short-handed against the Orioles on Thursday night. Toronto, which has yet to announce a corresponding roster move, will need to call someone up from the Minor Leagues for the coming weekend series against the Yankees.

McGowan left Tuesday night's start after four innings, complaining of pain in his right shoulder. It was determined that the 26-year-old pitcher had a tear in his right rotator cuff, which was further examined on Thursday. Toronto's team doctors found that, compared to an MRI exam performed on the pitcher's shoulder late last season, there was no new damage in McGowan's arm.

"There was a tear last year, as most pitchers have," Given said. "The tear at that point is consistent with the one this year. ... All I can say about McGowan is that it's really positive. If there was further damage to his tear it would've been a long rehab process for him.

"This is positive news that he's going to pitch sooner than what we feared the most."

That being the case, McGowan may have inflammation in his throwing arm, but will not likely need surgery. Dr. Timothy Kremchek will examine the results of McGowan's MRI results on Monday in order to provide a second opinion and the right-hander will meet with the arm specialist some time next week.

"Obviously, he still has some discomfort there," Given said. "So, we're going to have Dr. Kremchek examine both of his MRIs. We're going to start with a rehab next week, but we're just going to double-check with Kremchek and make sure we exhaust all the possibilities."

McGowan, who is 6-7 with a 4.37 ERA in 19 starts this year, is expected to miss at least a month, while working through a throwing program in preparation for a return to Toronto's rotation. For now, left-hander Brian Tallet will move from the bullpen to the rotation for a spot start on Sunday.

Jordan Bastian is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.