PHILADELPHIA (AP) _ Chris Welp, the Philadelphia 76ers' first-round draft choice, will miss the rest of this season and the early part of the next because of ligament and cartiledge tears in his left knee, the club announced Thursday.

Doctors discovered the damage during arthroscopic surgery Thursday.

The 7-foot Welp, from the University of Washington, collapsed twice Tuesday night during the 76ers' victory in Chicago over the Bulls. He felt only a twinge the first time and continued playing.

As late as Wednesday, Welp said the knee felt fine and questioned the need for the arthroscopic proceedure. But the knee swelled and Dr. Roy Moyer decided to go ahead with the exploratory operation.

Moyer said he would wait about two weeks before performing reconstructive surgery on the knee.

With proper rehabilitation and without a setback, Welp should be able to resume his basketball career, Moyer said.

Welp, the 16th pick overall in this year's NBA draft, had been used sparingly this season. He averaged 4.8 points and 2.4 rebounds in 10 games.

He is the second 7-foot center lost by the 76ers in recent weeks. Tim McCormick has been sidelined with a shoulder separation and is not expected back for two weeks.

The 76ers also are without 6-9 forward Roy Hinson, who is recovering from a broken finger and and is not expected to play before Wednesday.