Wallace was replaced in the starting lineup by Brian Scalabrine.
Celtics spokesman Jeff Twiss said a few minutes before the game that Wallace had trouble pushing off when he jumped so coach Doc Rivers decided to give him the night off.
Wallace was averaging 10 points and 4.5 rebounds per game.
Wallace's absence is a problem because he was replacing Kevin Garnett in the lineup. Garnett has not played since he hyperextended his right knee on Dec. 28, and Rivers said Monday that he expects him to miss another 10 days.
"He got to start working out today for the first time," Rivers said. "Now it's just a conditioning thing. We want to make sure he gets strong and back in shape because he literally hasn't done anything. We figure 10 days to two weeks, that's what it'll take."