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08/13/08 2:15 AM ET

Lowell hurts right rib cage

Red Sox third baseman injured taking swing in seventh

BOSTON -- Third baseman Mike Lowell, who has been battling a strained right hip flexor muscle for more than three months, could quite possibly go on the disabled list with a strained right oblique muscle.

Lowell left Tuesday's game after injuring the muscle in his right rib cage during a seventh-inning at-bat in the Red Sox's 19-17 win over the Rangers. Lowell struck out in the at-bat and was replaced on defense in the top of the eighth.

"This is kind of uncharted territory for me," Lowell said "I took a couple of swings and on the first one, I felt a little bit of a grab on my side. Then, on the second [swing], I felt something a lot more significant. I have never had this happen to me before. It's just frustrating for me."

Lowell will undergo an MRI on Wednesday morning before the Red Sox make an official decision, but there's little doubt he has some issues on the right side of his body.

"He's feeling it a little bit," manager Terry Francona said. "Everyone knows how tough he is and he'll play through things. We'll get him checked out in the morning. We're not going to rush into anything because of who he is and how he plays, but we'll get him checked out in the morning and try to get a medical update so we know how to proceed."

Lowell missed almost three weeks in April because of a sprained left thumb, but that was the first time he's been on the disabled list since he broke the same thumb in 2003. He has had the hip flexor injury, but has missed just one game because of it, and that was earlier this month against the Royals.

"I can't believe ... this hip situation," Lowell said. "I don't really see this as two totally different things. There's too much of a coincidence. It felt weird. I tried to bend over and grab at it and hoped it would go away. But it's gotten progressively worse, so it's frustrating."

Lowell was 1-for-4 on Tuesday and is now hitting .198 (23-for-116) with one home run and 13 RBIs in his past 29 games. When he came out, Kevin Youkilis moved over to third base and Sean Casey came in to play first. Both are hitting over .300 and that's the obvious configuration, should Lowell go on the disabled list.

"It's definitely bad," Youkilis said. "You don't want one of your key players to be out. But, hopefully, we have some guys that can step in and play. I'll slide over to play third and Sean Casey can play first. So that's a pretty good infield there.

"He was on the DL earlier in the year and we had to play a little bit better. ... We're confident that we can play good ball, but its definitely tough to lose a guy like Mike Lowell."

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