PHILADELPHIA (AP) -- Andrew Bynum wants to play in Philadelphia. He's not sure his achy knees will let him.
It was the story of Bynum's lone season in Philly.
It's the same refrain now that he's back in town with the Cleveland Cavaliers.
Bynum hopes to play Friday night against the team that acquired him in a blockbuster trade in the summer of 2012. He never played a second for the Sixers because of bone bruises in both knees. He had season-ending arthroscopic surgery in March.
With the Sixers in rebuilding mode, they had no interest in resigning the 7-foot Bynum. He signed a two-year, $24 million contract with Cleveland in July. Only one season is guaranteed and the team holds the option for next season.
Only 26, Bynum's days as a franchise center are over.
"It's still career-threatening," he said Thursday. "I'm a shell of myself right now on the court. I'm just struggling mentally. I'm trying."
Bynum has modest averages of 5.5 points and 3.5 rebounds in four games with the Cavaliers.
Bynum had his best NBA season for the Lakers in 2011-12, averaging career highs of 18.7 points and 11.8 rebounds while making his first All-Star team, starting for the West. He was the NBA's third-leading rebounder and 20th-leading scorer, while also ranking sixth in the league with 1.93 blocked shots per game.
After a surprising run to the Eastern Conference semifinals, the Sixers hoped Bynum would be the missing piece that would turn them into a regular contender. But there were problems with knees from the start. The Sixers held him out of training camp as a precaution, and various timetables -- often set by Bynum -- came and went with nothing to show for his rehabilitation.
The Sixers welcomed Bynum with a public press conference that whipped hundreds of fans into a frenzy. Without playing a game for the Sixers, he said he wanted to make Philadelphia his home -- and the team was ready to commit.
Instead, they spent almost $17 million for nothing.
"If I could've played, I would've," Bynum said. "And that's where that's at."
Bynum said he feels "sharp pains" in his knees and they were sore after a dunk in Wednesday's game against Milwaukee.
Before the Cavaliers gambled on him, Bynum flirted with retirement.
"It's a serious thought," he said. "It still is. It's tough to enjoy the game because of how I am physically. I'm certain I'll work through that."
