PHILADELPHIA -- Despite making an encouraging return from devastating knee injuries, Andrew Bynum is still pondering whether to continue to play and battle ongoing knee pain or retire.

On Friday, Bynum hopes to do something he wasn't able to do all of last season -- play in Philadelphia. He missed the 2012-13 season with knee issues after the 76ers executed a major trade for him and planned to make him a franchise cornerstone.

But even as he's defied the odds by returning to play with the Cleveland Cavaliers, Bynum is still in discomfort following surgeries to both knees earlier this year.

"Retirement was a thought, it was a serious thought. It still is," Bynum, 26, said after Cavs' practice at Temple University. "It's tough to enjoy the game because of how limited I am physically. I'm working through that. Every now and again I do [think about retirement]. … It's still career-threatening. I'm a shell of myself on the court right now. I'm just struggling mentally."

Bynum is expecting to get a rough reception Friday night. There was a perception that he didn't make his rehab a priority while he was with the 76ers, especially after he admitted he reinjured his knee while bowling during the season. Several times he was on the verge of returning to play only to have a setback.

"If I could've played I would have," Bynum said. "I don't really care [how the fans will treat him]. It is what it is. I was hurt and I'm still hurt but I'm trying. … Nothing went bad, nothing went wrong. I think people just need to accept the facts that my knees are the way they are."