Pierce sits out with shoulder pain

Boston Celtics captain Paul Pierce suffered a shoulder stinger Tuesday on the same shoulder he tweaked in Sunday's loss to the San Antonio Spurs, chasing him from practice and leaving him questionable for Wednesday's game against the Oklahoma City Thunder.

According to coach Doc Rivers, Pierce got hit on a back pick and went down clutching the same shoulder that he dubbed "sore" after getting fouled by Manu Ginobili in the third quarter of Sunday's game.

"He got hurt again today -- the same thing, a stinger, with the same exact reaction," said Rivers. "It looked worse today ... I guess a stinger will be fine. You get concerned with two in a row -- a game and a practice -- the exact same thing. He got hit and went down.

"The good news is that it's not a shoulder separation or anything. Worse case, he misses a game or two," Rivers said. "That's not all bad. You'd rather have him, but at least it's not a lower-body injury."

Pierce has missed 10 games this season with a hodgepodge of injuries, including a right knee infection, sprained left midfoot, and a sprained right thumb.

Pierce left Sunday's game shortly after the injury (he stayed in to attempt two free throws, missing the first), but refused examination from trainer Ed Lacerte and soon re-entered the game. He finished with a team-high 18 points (five of which came after the injury).

"It's a little sore," Pierce said after the game. "It's a stinger -- I've got some numbness down the right side of my arm, but hopefully it doesn't get any worse."

Pierce finished 4-of-11 shooting that night, missing all three 3-pointers he attempted and generating 10 of his points at the foul line. It was only the second game in his last six that he's been held below 22 points.

Meanwhile, Celtics center Kendrick Perkins returned to practice Tuesday and deemed himself ready to play Wednesday night against Oklahoma City.

Perkins sat out two games (and a practice) last week in hopes of preventing the tendinitis in his left knee from worsening, which afforded him nearly a full week off. He gave a positive report after Tuesday's session, while noting there was lingering stiffness.

"I felt alright, I thought I played pretty good at practice today," said Perkins. "My knee felt better. I'm looking forward to going out there and playing [Wednesday].

"There's a little bit [of stiffness]. It's probably something I'll have to deal with the rest of the season. I'll continue to get treatment, continue to come in at night and get that treatment."

Perkins also admitted he's been battling the tendinitis for as much as two months before he finally took the advice of Rivers and the training staff and shut it down for the week. Perkins begrudgingly noted the injury has likely affected his game.

"I can't get up and block shots like I want to, I can't get up for the rebounds," said Perkins. "But I'm out there, so I gotta get the job done. I'm not making excuses, but I think it has [affected his play] in a way."

While the Celtics certainly missed Perkins' presence the past two games, Rasheed Wallace, who started in his place both games, noted after Sunday's loss that, "Our main thing is to get Perk healthy. Take a couple games off, lay off them knees for a minute, and come back with fresh legs."

Chris Forsberg is the Celtics reporter for ESPNBoston.com. Follow him on Twitter.