BOSTON — Andrew Bynum watched "Big Baby" and Boston batter his Lakers, believing all along he could have made a difference.

So even with a sore right knee that became impossible to play on in Game 4, Bynum wants to be on the floor Sunday night for the most important game of the season.

Phil Jackson plans to let him — on one condition.

"We'll use him if he's available and able, but we're certainly not going to put him in a situation that's either going to hurt himself or the team," Jackson said Friday.

Jackson said he doesn't have "any expectations" for his injured center, but thinks the Lakers can win even without him.

"We're going to try and establish the fact that we're going back to L.A. with a 3-2 lead," Jackson said. "We believe we can do it. We felt we let one get away last night."

More like the rougher and tougher Celtics took it.

With Bynum limited to only 12 minutes and on the bench for nearly the entire second half, Boston pounded Los Angeles inside in a 96-89 victory that tied the series at two games apiece.

The Celtics had a 54-34 advantage in points in the paint, with Glen Davis and Boston's bigs finding room in the areas that Bynum often controls.

"They miss him," Boston coach Doc Rivers said. "I mean, he has great size and length, and we attacked the paint yesterday, and Andrew wasn't there. So I mean, obviously when he's not on the floor, there's a big difference."

Neither team practiced Friday, the first of two days off before Game 5. The break comes at a good time for the Lakers, with Jackson saying he thought Kobe Bryant looked tired late in Thursday's game.