By Gary Washburn, Globe Staff

Celtics coach Doc Rivers said the right calf strain suffered by Shaquille O'Neal early in the second quarter was "minor" and he is not expected to miss extensive time. But there is no word on when he will return. O'Neal left TD Garden walking with a slight limp and it appears the injury looked worse that doctors discovered it was.

O'Neal missed 27 games with foot and Achilles' tendon injuries and was making his first appearance since Feb. 1.

"The update is that it’s not the same injury," Rivers said. "Had nothing to do with the Achilles; it’s a calf strain. It’s not a bad strain, but it’s a strain. So similar to the one Von (Wafer) had but not even close to the severity. Well, ‘I don’t know (when he will be back)’ is the answer. I don’t think very long, honestly. That’s what (Dr.) McKeon and them thought, that it’s very minor. Scary, more than anything. And you know I’m sure with the calf that he probably thought Achilles right away. But we’ll see."

Kevin Garnett missed nine games with a strained right calf while Wafer missed 13 games with the same injury.

O'Neal was running the floor on a fastbreak after Jeff Green blocked Jason Maxiell's shot and pulled up lame near midcourt, motioning to the bench to call a timeout. O'Neal then lumbered towards the tunnel, writhing in pain and couldn't make it to the Celtics locker room. He rejected the offer for a wheelchair and finally limped to the trainer's room to be examined.

The Celtics practice Monday in Waltham before facing the Philadelphia 76ers on Tuesday. Center Nenad Krstic, who sustained a bone bruise in his right knee Thursday against San Antonio, could return to action for that game.