Portland’s No. 1 draft pick is out for his first season.

More: Blazers statement on Greg Oden

Greg Oden underwent exploratory knee surgery Thursday and doctors said it revealed cartilage damage to the rookie’s right knee, according to the Blazers.

The Blazers confirmed at a news conference Thursday afternoon that Oden would be out for the entire season, to give his knee time to heal. Oden was expected to leave the hospital sometime Thursday.

Survey: Share your comments

Blog: What is micro fracture surgery?

More: Oden's bio

“The area of injury was not large and we were able to treat it with micro fracture (surgery), which stimulates the growth of cartilage,” Team physician Dr. Don Roberts, who preformed the surgery, said. “There are things about this that are positive for Greg. First of all he is young. The area where the damage was is small and the rest of his knee looked normal. All those are good signs for a complete recovery from micro fracture surgery."

Also: Oden's blog

Doctors said recovery generally takes between six and 12 months and Oden was expected to be on crutches for up to eight weeks.

The surgery was a complete success and there was no need for further operations anytime soon, doctors told the team.

"Greg looked at me as he was coming out of surgery, him and his mom probably said sorry 20 times," General Manager Kevin Pritchard said. He added that no matter what, the Blazers were very lucky to have Oden.

"He hasn't let us down at all," Pritchard said.

Coach Nate McMillan said it was all a part of the game.

"Injuries, surgeries are a part of sports." He added that as important as Oden is, it was all about the team.

"It makes us a little thinner," in terms of strategy, McMillan said. But he added that the depth, versatility and youth of the team would allow them to fill in for Oden.

It was unclear exactly how Oden injured his knee. Pritchard said he noticed it while on a treadmill last week.

Pritchard said it was hard to put an exact timetable on for Oden's recovery, but it was likely he would not be able to come back by the end of the season.

"Certainly this is a setback, but our future is still incredibly bright," Pritchard said. "Is it disappointing? Yes. However, this is a great core of talent and players of strong character and will continue to be."

Oden was the hotly anticipated pick after the Blazers scored the number one selection for the 2007-2008 season.

The Blazers open training camp on Oct. 2. The regular season opener is at San Antonio on Oct. 30.

VIDEO: Oden dances into downtown

VIDEO: Oden draft night interview

"We know this discouraging news for all of our fans, however, the people of Portland are very enthusiastic and compassionate about their Trail Blazers and I know they will stand behind Greg and the team during his recovery," team President Larry Miller said.

Oden has a fully guaranteed contract, and coach McMillan said he wanted Oden to spend his recovery with teammates as much as possible.

Some fans were quick to compare the situation to that of second round draft pick Sam Bowie in 1984, who failed to meet expectations after developing knee problems, but Blazers were optimistic Oden's situation was different.

More: Who is Sam Bowie?

"The one thing I know is we picked the right player," Pritchard said, adding that Oden is a great human being.

"There's so much anticipation, not only form our fans and the organization, but from national media to see Greg play. That is a setback, a disappointment for basketball," McMillan said. "But the decision we made we feel was the right decision. Greg Oden was our man -- he still is our man."

It's Oden's second health problem since joining the team -- over the summer, he had his tonsils taken out.