Is the kneecap dislocated?
"Really not sure," Stafford said Thursday after missing a second straight practice.
Will he play Sunday against the Pittsburgh Steelers?
"I don't know," he said. "We'll see."
Lions coach Jim Schwartz refused to be remotely forthcoming when asked for an update on his rookie quarterback.
"The injury report will be out at 4 o'clock," Schwartz said during a terse interview session that lasted about 20 seconds.
Detroit's injury report listed Stafford as one of its players who did not practice Thursday because of a knee injury.
Stafford had his right knee twisted on a sack in Sunday's loss at Chicago.
"Obviously any time you tweak something, it's scary," he said.
Stafford, the No. 1 pick in the NFL draft, said he did get good news from tests because there was no structural damage and surgery wasn't deemed necessary.
The Lions, though, hadn't cleared him to run four days after he was injured.
"They're just trying to get the swelling out," Stafford said.
Daunte Culpepper would start in Stafford's place if he can't play, but Culpepper is not yet interested in discussing anything with reporters.
"I have nothing to say until something changes from my perspective," Culpepper said.
Stafford said he hurt the same knee in high school -- during a freak accident on a Slip 'N Slide, according to his father -- but it was a different injury.
"I had a sprained MCL and a bunch of other stuff," Stafford said.
After Stafford spoke with reporters, one of them said his kneecap looked good.
"It's in the front," Stafford joked as he touched his right knee.