Bill Walker, F, 6-6, Kansas State -- Might be a diamond in the rough if his knee problems are solved. Acquired in draft night deal for cash with Washington.

Semih Erden, C, 6-11, Turkey -- Tough inside player who has one year left on his Turkish League contract. A pick for the future.

BIGGEST NEEDS: The Celtics would like to solidify the center position. Kendrick Perkins is still their guy, but he missed Game 5 of the Finals with a left shoulder problem that has dogged him in the past. Even assuming he is fine, they'd like to be more certain of who backs him up. Scot Pollard had the job before injuries got to him. Then veteran P.J. Brown came in late and was tremendous. But will he retire?

FREE AGENT FOCUS: The Celtics didn't get to keep James Posey, but Tony Allen and Eddie House are staying. Patrick O'Bryant was signed as a backup center, but the club is still looking for a veteran in the P.J. Brown mold.

PLAYER NOTES:

--G/F Tony Allen has been increasing his offseason work, hoping to take advantage of the available playing time with James Posey gone. Allen lost the trust of his coaches last season due to inconsistency as he came back from knee surgery, and he wants to avoid a similar situation.

--F Paul Pierce has the all-clear on his right knee. He had an MRI on the knee he injured during the NBA Finals, and it showed nothing serious.

"It's what we thought all along," said Danny Ainge. "He had a sprained MCL and a bone bruise, and he'll be fine."

--G Gabe Pruitt has been getting extra tutoring on playing the point. The Celtics would like to see him take steps forward in running the offense as he enters his second season.