Boston Celtics centre 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 six-foot-nine. 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.