Celtics center Jermaine O'Neal has returned to Boston amid the team's road trip to get a second opinion on his injured left knee.

O'Neal will not be available for Saturday night's game in Memphis as Boston concludes a four-game road trip.

"I'm going to get a second opinion, just a thing that a player should do," O'Neal said before Boston's game against the Heat in Miami on Thursday night. "Obviously, I believe in our staff a lot, I support our doctors and we have some of the best doctors in the world. But I just want to get a different opinion, see if everybody's on the same page. This is the third time it's blown up on me, so I have to do something.

"Obviously, I'm new to the team. I know our doctors have checked over my records, but being [in Miami] for two years, they dealt with it and I didn't have any issues when I was here. [The knee] was strong, so I'm just kinda getting their opinion, then putting it with our doctors and getting them together for a conclusion on why the knee is blowing up the way it's blowing up."