PORTLAND, Ore. -- Trail Blazers center Greg Oden underwent an arthroscopic procedure to "remove debris" from his right knee, his fourth surgery since Portland selected him with the No. 1 pick in the 2007 draft, the team said.
The often-injured 7-footer had microfracture surgery on the same knee before the start of his rookie season, forcing him to postpone his NBA debut for a year.
Since then, Oden has appeared in just 82 career games for the Blazers, averaging 9.4 points and 7.3 rebounds.
Oden hasn't appeared in a game for the Blazers in two years. He also underwent surgery for a fractured kneecap in late 2009, then early last season he had microfracture surgery on his left knee.
The latest procedure took place Friday afternoon in Vail, Colo. The Blazers said it was successful and that Oden remains out indefinitely.
It was expected that he might be able to play for the Blazers this season, but a checkup before the start of training camp in December reportedly revealed concerns about a non-weight-bearing ligament in the left knee, further setting back his rehabilitation. Since then, he has turned down repeated interview requests.
Oden was a restricted free agent heading into this season. The Blazers and Oden initially agreed to an $8.9 million qualifying offer for this year, but when the setback was announced the two sides restructured the deal, which was dropped to $1.5 million.
He will become an unrestricted free agent following this season.
Oden was selected over Oklahoma City's Kevin Durant with the top pick in the 2007 draft. The Blazers believed the former Ohio State star could lead the team -- along with Brandon Roy and LaMarcus Aldridge -- to an NBA championship.
But the trio has seen only scant playing time together, and Roy, a three-time All-Star, abruptly retired before the start of this season because of his own ongoing knee issues.
While Bowie played in 76 games his rookie season, averaging 10 points and 8.6 rebounds, he appeared in just 63 games over the next four seasons because of injuries. He missed the entire 1987-88 season. In all, he had five operations on his legs.