PORTLAND, Ore. (AP) – Trail Blazers center Greg Oden, the No. 1 pick in the NBA draft, will undergo exploratory arthroscopic knee surgery this week because of pain in his right knee.

An MRI taken last week showed Oden may have some cartilage problems, general manager Kevin Pritchard said Monday.

A timetable for Oden’s return will be set following the surgery, which will take place Thursday in Vancouver, Wash.

This is Oden’s second health problem since the Trail Blazers drafted him in June. He had a tonsillectomy in July after struggling in two Las Vegas summer league games.