Woods, a junior who was an ESPN.com All American in 2011, underwent arthroscopic surgery on his injured right ankle in December and was scheduled to return for spring practice in March. But he has yet to be medically cleared by university doctors with lingering inflammation in the joint.
"Our reports have not said that he'll be 100 percent," Kiffin said Tuesday when asked about Woods' status. "Obviously, we would like for that to be case. But until I can physically get with him, which I'm not allowed to right now, and see him move around, I can't really tell myself where exactly he is."
Woods has been dealing with the ankle injury since a pick-up basketball game on the eve of USC's spring game in April 2011, but he played through it last season and totaled 1,292 receiving yards on 111 receptions, including 15 touchdowns.
He told ESPNLosAngeles.com last month he was not overly worried about his health heading into the 2012 season.
"I thought about it, the possibility of not being healthy for the season, of still being sore," Woods said. "But then I remembered I was sore all last year and I did OK, so I think I'll be alright."
Woods, 20, has not practiced with the Trojans since the end of the 2011 season and has been unable to run for much of the summer. Kiffin lamented that to the media on Tuesday.
"It just never recovered the way it was supposed to," Kiffin said. "For whatever reason, there's just been setbacks during the recovery and he's still not there."
USC officially starts fall camp practices on Aug. 6.