Former Ohio State center Greg Oden underwent an arthroscopic procedure Friday in Vail, Colo., to remove debris from his right knee, the Portland Trail Blazers announced. It is his fourth knee surgery since the NBA selected the 7-foot Oden with the first overall pick in the 2007 draft.

Blazers interim general manager Chad Buchanan said it’s too early to tell if the procedure will end Oden’s season.

“That would be speculation at this point,” Buchanan told The Oregonian newspaper. “We are going to continue to stand by and support Greg and listen to what the doctors have to say after the surgery.”

The team has not commented since then but did announce that Oden will undergo the same procedure on Feb. 13. One report said he also is dealing with blood clots in his ankle.

The Feb. 13 procedure will be Oden’s fifth surgery since entering the league. He arrived to Ohio State as damaged goods and needed surgery to repair a wrist injury.

Oden’s right knee has not given him problems since 2007, when he had microfracture performed before the season started.

His left knee was the knee in question during his December visit to Colorado, when the team deemed he had suffered a setback because of an issue with a non-weight bearing ligament in his knee.

Buchanan said Oden recently started “increased activities” on the basketball court, during which Oden had good days and bad days with his knees. After a recent magnetic resonance imaging, doctors at the Steadman Clinic in Vail detected debris in his right knee and decided they wanted to operate to clear the debris and to take a closer look.

Oden, who turned 24 last month, has not played in an NBA game since December of 2009, when he fractured his left patella. After rehabilitating from that injury, Oden never made it back, having to undergo microfracture surgery on his left knee in November of 2010.

The team had hoped he would return this season, and extended an $8.9 million qualifying offer, which Oden accepted. However, after the December doctor’s visit in Colorado, during which the team deemed he had suffered a setback, the Blazers and Oden’s representatives negotiated a reduced salary, believed to be around $1.5 million for this season.

Since entering the league in the fall of 2007, Oden has played in 82 games, the equivalent of one NBA season. He has career averages of 9.4 points and 7.3 rebounds.