"We'll evaluate him again tonight, evaluate him again in the morning," Kiffin said. "He came in today and felt he couldn't go during practice, so Josh took the majority of the snaps."
Culpepper apparently injured himself during the Raiders' 20-17 win over Kansas City last week but didn't become a problem until he tried to practice Wednesday and had to be held out of some drills.
Josh McCown, who has started five games for Oakland this season, ran the first team offense in practice Friday after taking increased reps the day before. Rookie JaMarcus Russell also took reps with the starting offense, though Kiffin wouldn't reveal what his depth chart would be against the Broncos.
"There's a lot of information still to come in," Kiffin said. "I don't have an answer for you who's 1-2-3 right now. If it goes down to taking it down to warm-up, we'll do that."
Kiffin did say that it was safe to assume McCown will start against Denver if Culpepper cannot.
McCown, who had to have stitches in his left (non-throwing) hand after dislocating a pair of joints in his pinky which caused the bone to break through the skin, doesn't think his condition will affect him too much.
"I don't think I'll have to numb it at all," McCown said. "It felt pretty good today. The way we rig it up is I'm wearing a glove and it's more tacky than, obviously, your skin. So between those three fingers, that helps when I'm holding the ball."