Nerlens Noel has had surgery on his sore left knee, and the Sixers have not disclosed a timetable for the disgruntled center's return.

Noel has been out since the team's first preseason game. He initially had a left groin strain before experiencing soreness in the knee during rehab, and it was discovered he had an inflamed plica. 

The team is calling the surgery a "minor elective arthroscopic procedure." It was performed in New York by Dr. Riley J. Williams at the Hospital for Special Surgery.

Noel eventually will travel to Birmingham, Ala. to rehab with associate clinical director Kevin Wilk at Champion Sports Medicine.

The Sixers expect to have a timetable for his return once Noel returns to Philadelphia. According to Keith Pompey of The Philadelphia Inquirer, Noel is expected to miss three to five weeks. 

This has been a rough preseason for Noel, who hasn't hidden his displeasure with his role on the Sixers' jammed frontcourt. The team has until Oct. 31 to extend his rookie contract but, per a report in the Inquirer earlier this month, the two sides have yet to discuss it.