The Portland Trail Blazers announced on Friday that center Greg Oden will undergo an arthroscopic procedure on his right knee in Vail, CO, today to remove debris. Oden had microfracture surgery on his right knee in September 2007.

Update : The team announced this afternoon that the procedure was "successful."

Oden's most recent injuries have been to his left knee. Oden underwent microfracture surgery on his left knee in November 2010 after fracturing his left patella in December 2009.

Blazers Acting GM Chad Buchanan told Blazersedge on Friday that Oden could undergo a similar procedure on his left knee as well.

"That's a possibility. There's a chance that he may go undergo a similar procedure on his left knee in the coming days," Buchanan said. "That is to be determined. The doctors felt like after looking at the latest MRI in both knees, they wanted to take a closer look at both things. It's still to be determined on his left knee."

The Blazers announced back in December that they were "hopeful, but less confident" that Oden would be able to return to the court this season because he had suffered a "setback." There is no set timetable for his return. In early January, Buchanan said that Oden was "taking the next step" in his rehabilitation.

"For his timeline, he's still considered out indefinitely," Buchanan said on Friday. "There's really no timetable at this point. We're going to kind of listen to the doctors after they get in there and look at his right knee today and then listen to what they feel needs to be done and what the timetable for his return may be. It would be purely speculation until we get more information from the doctors."

Marc Stein of ESPN.com reported in December that Oden had agreed to renegotiate his $8.8 million qualifying offer down to $1.5 million after the setback was announced. A report by Jason Quick of The Oregonian indicated that the setback was related to a non-weight bearing ligament in his left knee.

Buchanan said that the issue leading to Friday's procedure "was just one of the possibilities" and not necessarily the setback described in the team's December press release.

He also did not rule out further surgeries or procedures for Oden after these potential arthroscopic procedures on both knees.

"It's hard to eliminate anything at this point," he said.

Buchanan said he "didn't know for sure" whether Friday's procedure on the right knee was a direct result of the 2007 microfracture surgery or not.

"He's increased some of his activity level, the doctors aren't really sure what is the direct reason for it," Buchanan said. "It would just be speculation on our part to try to pinpoint."

Oden will be an unrestricted free agent this summer.

"Greg had some good days and some bad days like anybody returning from injury and we're going to listen to the doctors as to what they advise for Greg," Buchanan said. "We're going to continue to support him and stand by him through this. We knew this was a possibility when we signed Greg at the beginning of the year, as did Greg, so it is a setback but we were prepared that it could be a possibility."

Oden, 24, has played in 82 games since being drafted as the No. 1 pick in the 2007 NBA Draft and has not appeared in a game since December 2009. Oden has posted career averages of 9.4 points, 7.3 rebounds and 1.4 blocks per game.

Update : The following message was posted on Oden's Facebook page, as noted by philthebballplayer in the FanShots.

I'm sure you've all heard the news by now that I'm having a scope on my knee today. Unfortunately after months of intense rehab and training, the doctors discovered that a scope is necessary at this time. Thankfully this should be a quick recovery and I'll be back to training soon. I'm committed as ever to doing everything and anything to get back on the court and be a part of the team's success. Thanks for all the support, your well-wishes are much-appreciated. Good luck to my teammates this weekend!

-- Ben Golliver | benjamin.golliver@gmail.com | Twitter