WALTHAM, Mass. - Boston All-Star Paul Pierce left Wednesday night's game in the opening minutes of the first quarter with a lower back strain, only to return and score 14 points on 5-of-10 shooting, with 4 rebounds, 2 assists, and 2 steals.

He said that he won't miss Game Three because of the minor injury.

"My back's a little sore," Pierce said. "Obviously I took a hard hit in the first quarter, but I'll get some treatment, rest it up for the next couple of days, and I think it will be fine."

Pierce hit the floor hard when he collided with Atlanta forward Al Horford in midair, and Hawks teammate Josh Smith landed on top of him.

Pierce went to the locker room to receive treatment. He started the second half and played 28 minutes in the game.

"I jumped right up to see how I felt," Pierce said. "When I got to half court I felt a little pain in the back. Just take your lumps and bruises in the playoffs and move on."

Trying to match Boston's intensity in Game One, Atlanta played a much more physical game Wednesday night. Pierce said he isn't bothered by Atlanta's physical play.

"Not really," he said. "I understand that's what the playoffs is all about. You've just got to be ready. Teams are going to be physical with you when you get inside the paint.

"I don't know what they're trying to do. They're trying to play physical; they're trying to do what they can to get a win just like we are. I don't think there's anything illegal or dirty about the play."

James Posey replaced Pierce when he left the court. Posey scored nine points and pulled down five rebounds.

"I was concerned about Paul, but Posey was terrific," Boston coach Doc Rivers said.

Team gets a breather

The Celtics had the day off yesterday. They were given film to watch. They go back to practice today at 11 a.m. before leaving for Atlanta this afternoon.