BOSTON - Celtics center Michael Olowokandi will be sidelined two to four weeks because of a slight tear in his abdominal muscle, the team said Friday.

Olowokandi had four points and four rebounds in Boston's 114-88 win over Indiana on Wednesday, but sat out Thursday's practice with pain in his stomach. He had an MRI exam Thursday night, revealing a small tear.

"It's worse than I guess we thought," Celtics coach Doc Rivers said. "Michael actually wanted to get a shot to play, and then when they found out it was a small tear they obviously ruled that out."

Olowokandi joins Al Jefferson and Theo Ratliff on the bench, leaving Kendrick Perkins as Boston's only healthy player taller than 6-foot-9. Jefferson missed his sixth game Friday after getting his appendix removed on Nov. 8, and Ratliff has played only two games while suffering from lower back pain.

"We just have to get through this and pray that (Perkins) stays out of foul trouble," Rivers said. "The problem is he can't play 48 minutes."

Ratliff could miss several more weeks, but Rivers said he expects Jefferson to return late next week.