Philadelphia 76ers general manager Tony DiLeo said Friday that Andrew Bynum has been cleared to increase activity with his rehab plan, but there is still no timetable for his return.

Bynum, acquired by the Sixers from the Lakers in August as part of the four- team, 12-player blockbuster trade that sent Dwight Howard from Orlando to Los Angeles, has yet to play for Philadelphia this season due to problems with both of his knees.

The 25-year-old Bynum, who has a history of troubles with both knees, was diagnosed with a bone bruise of the right knee in September. It was then reported in November that Bynum hurt his left knee while bowling.

The Sixers said in late November that Bynum would be out indefinitely, but they were hoping for him to return in January.

Bynum visited a knee specialist in New York City on Thursday, and DiLeo provided an update Friday.

"Andrew met with Dr. Altchek up in New York. The report is that his knees are healing, he is improving," DiLeo said. "He has been approved to increase his activity level, (but) still there is no timetable. A lot depends on how Andrew reacts and his body reacts to the increased activity. We do have a revised rehab plan that we put together with our medical people and his doctor. Basically, we'll go through that and as he goes through these different phases of the rehab program, if he reacts in a positive way then we go into the next step. Basically, it's probably a six-step process from low-impact to getting him on the court playing basketball."

DiLeo added that the bone bruises are healing and the weakened cartilage state is improving.

Bynum also spoke with the media on Friday.

"We are working together. Obviously the doctors are taking their time because I want to play for 10-12 more years and not two," Bynum said. "So I think the biggest thing here is to take our time and get it done right."

Bynum appeared in 60 games and averaged 18.7 points with 11.8 rebounds for the Lakers last season.

DiLeo continued to defend the trade the Sixers made during the summer. It was a deal that sent All-Star forward Andre Iguodala from Philadelphia to Denver.

"We would still make the move knowing what happened. Are we disappointed that it hasn't worked out sooner? Of course," DiLeo said.