PORTLAND — Center Greg Oden, Portland’s often-injured former No. 1 draft pick, will sign the Trail Blazers’ $8.9 million qualifying offer today, Oden’s agent said.

Agent Bill Duffy confirmed Thursday that Oden would sign the one-year deal when the team opens training camp. But it is not clear when Oden, who is coming off left knee surgery, might be available to play for the Blazers.

The deal, first reported by The Oregonian newspaper, means that Oden will become an unrestricted free agent after this season.

The Trail Blazers would not comment on the agreement, which cannot be formally completed until Friday. Oden was in Colorado having his knee examined.

It wasn’t known whether he would join his teammates for the first day of camp.

Oden missed all last season after microfracture surgery on his left knee. An earlier microfracture surgery on his right knee postponed his rookie season after the Blazers took the 7-foot center with the first pick of the 2007 NBA draft.

The Blazers made the qualifying offer on June 29. Oden could either accept the offer, or wait to see if other teams were interested in him. The Blazers would have three days to match any other offers.

Because of various injuries, the former Ohio State star has played in only 82 games over parts of two seasons, averaging 9.4 points and 7.3 rebounds. In addition to the two season-ending surgeries, Oden broke his left kneecap and sat out much of the 2009-10 season.

It is not expected that Oden will be able to practice, or play, right away. The Blazers play the first of two preseason games against the Utah Jazz on Dec. 19 at the Rose Garden.

The Blazers open the season at home against Philadelphia on Dec. 26.

Earlier this week, acting general manager Chad Buchanan discussed the prospects of having Oden return to Portland. “We’ve shown a lot of commitment to Greg, both on and off the court, and I think Greg feels like he has some unfinished business here,” Buchanan said.

There was speculation that Oden might be able to play in late January or early February, but Buchanan said that decision would be made by Oden.

“As far as his timetable for return, we’re going to support Greg. When he’s ready to play, he’s ready to play. We’re not going to put a date on his return,” Buchanan said earlier this week.