It's not that knee, but Kendrick Perkins is still hurt enough that he's reportedly going to miss some time.
"Perk's got a mild sprain of his MCL," Celtics director of basketball operations Danny Ainge said, according to the Boston Herald. "He'll probably be out a week."
Perkins injured his right knee in Game 6 of last season's NBA Finals, had surgery on his anterior cruciate ligament and missed the first 43 games this year.
"I was like, [expletive], man. Not again," Ainge said, according to the Herald. "I was like, it can't be that. It definitely runs through your mind. I mean, I knew it was something that wasn't right. But after a minute, I knew it wasn't that serious, either."
Since returning, Perkins is averaging 7.3 points and 8.1 rebounds per game.
The Celtics are struggling to put a center on the floor, with Shaquille O'Neal and Jermaine O'Neal both out with injuries. Rookie Semih Erden returned to the lineup Tuesday after missing time with a strained muscle.
"Shaq's timetable is the same," Ainge said, according to the newspaper. "We're looking at him playing next week."
The Celtics play Thursday in Denver against the new-look Nuggets; Saturday against Blake Griffin and the Clippers in Los Angeles; and Monday in Utah against a Jazz team that just traded Deron Williams to the Nets.
Comcast SportsNet New England first reported Perkins' injury.