BOSTON -- Third baseman Mike Lowell, who had to leave Tuesday night's game because of a strained oblique, was placed on the 15-day disabled list by the Red Sox this afternoon.

Replacing him on the roster, at least temporarily, is pitcher David Pauley. The right-hander was called up from Pawtucket as an extra arm for the Sox, whose bullpen was taxed in Tuesday night's 19-17 victory over the Texas Rangers.

Manager Terry Francona indicated that if tonight's game moves along without any other injury issues, Pauley likely will return to Pawtucket after the game. And if that does come to pass, the Red Sox are expected to add a position player to replace Lowell.

"He's here to fortify our 'pen," said Francona of Pauley.

Francona said Lowell underwent an MRI this morning. The manager said the team is hoping his recovery time will be at the shorter end of the spectrum, but acknowledged that "these things have a way of nagging you."

Lowell was in the clubhouse yesterday, but no one had to ask him how he felt. His posture said more than enough. The third baseman was moving gingerly, a bit bent over from the waist.

"It's disappointing," he said. "I take a lot of pride on getting myself ready for the season and getting myself ready to play every day.

"We're on a run that's very important to our team this year. You want to have all the guys you're counting on. I think if anything, we have some really good depth with Sean Casey. He proved that he could swing a good bat for us earlier in the season. Hopefully he can do that again at this time of the season."

Lowell admitted he was uncomfortable with the oblique strain.

"As long as I can walk in a straight line, it's fine. It's the little twists and turns, things you take for granted, that kind of bite at you," he said. "I think the main thing right now is [to get] rest to calm it down, and then little by little strengthen it. I guess my main job is to be a cheerleader now."

The plan is for Lowell to do as little as possible for the next week or so, and to decide how to progress from there.

"They tell me the day you feel good, you've got to take a few more days, because the oblique is something we use so much, throwing and hitting," he said. "I guess it's better to be safe than sorry."

"I've never had this, so I don't know how it's going to affect me, but I'm going to do everything in more power to get back as quick as possible," he added.

Lowell, who was on the DL from April 10 to 29 because of a sprained left thumb, also has been battling a right hip flexor. His absence caused Francona to make a few lineup switches. Tonight, Kevin Youkilis is moving from first to third, with Sean Casey taking over from Youkilis at first base.

"You can't replace a guy like Mike Lowell, but I'll go in there and do the best I can," Casey said.