Doc Rivers rules Shaquille O'Neal out

NEW YORK -- Boston Celtics coach Doc Rivers ruled Shaquille O'Neal out for Sunday's Game 4 of the Eastern Conference quarterfinals against the New York Knicks, noting the 39-year-old center simply is not ready for game action.

O'Neal was present at Madison Square Garden on Saturday as the Celtics engaged in a walk-through after watching film at the team hotel.

"He's not playing [Sunday]," said Rivers. "We didn't do anything to see honestly. We didn't practice, we just walked through. I'm not going to put him out on the floor."

Before the Celtics trekked to New York on Thursday, Rivers indicated that O'Neal's traveling with the team would be an indication he could be back on the court as early as Sunday's Game 4.

But O'Neal still hasn't engaged in any heightened activity that would suggest he's ready to resume the rigors of game action.

With the Celtics on the verge of closing out the Knicks, boasting a 3-0 series lead, there's potential for as much as a full week off before the start of the conference semifinals (depending on the outcome of the Heat-76ers series, which Miami leads 3-0, with Game 4 on Sunday in Philadelphia).

Rivers did note that, if O'Neal was game-ready, the team wouldn't hesitate to put him back on the floor.

"[He'd] play, because I think he needs to play," Rivers said when asked if he would have utilized O'Neal even with a lopsided series edge. "I think he needs games and I think he needs practices. If he could play [Sunday], we'd play him a little bit, just because the fact that he hasn't had a practice, but he needs live basketball."

Chris Forsberg covers the Celtics for ESPNBoston.com. Information from The Associated Press was used in this report.