Greg Oden, the Portland Trail Blazers' No. 1 pick in the 2007 NBA Draft, will miss the 2007-2008 season after knee surgery on Thursday, two league sources told Yahoo! Sports.

Oden, the 7-footer out of Ohio State, underwent exploratory surgery on his right knee on Thursday in Vancouver. The extent of the damage was not immediately clear, but Oden, one of the most celebrated young players in years, will be lost for the season.

The Blazers are expected to make an announcement shortly.