"That is just a tough injury for a kid who has done everything right," Rivers said.

With star Kevin Garnett already out with a strained right knee, the injury to another power forward hits the Celtics at a bad time. Boston beat Chicago 118-115 on Monday night to even their best-of-seven series at one game apiece.

"I feel bad for him," Bulls guard Ben Gordon said. "Anytime somebody has that severe an injury, that's every athlete's worst nightmare. Our best wishes go out to him, but they still have other big guys."

Celtics forward Brian Scalabrine, who is recovering from concussions and has played just 60 minutes since Jan. 25, has been cleared to practice on Wednesday. Point guard Rajon Rondo is nursing a sore ankle and won't practice, but Rivers said he will play in Game 3 on Thursday in Chicago.

"We have all hands on deck now," Rivers said.

Rivers said Powe hurt himself on a spin move but stayed on the court trying to play.

"He played 3 minutes with a torn ACL," Rivers said. "That says so much about Leon Powe the person."

Powe averaged 7.7 points and 4.9 rebounds per game this season, missing 13 straight games down the stretch with a different injury in his right knee. He returned for the last two games of the regular season and was expected to have increased responsibilities because of Garnett's absence.

"Obviously, with Garnett out and Powe out, that's to our advantage," Bulls coach Vinny Del Negro said, "but you hate to see guys get injured."

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