McCown wore a protective boot around his foot but did not work out and has not practiced since suffering the injury during the first half of last week's win over Cleveland.
With the bye coming next week, it would seem the Raiders would lean toward giving McCown -- who also has a broken bone in his right foot -- extra time to rest. Yet Kiffin refuses to rule McCown out.
"We'll take a look at him in the morning again and see if he can practice tomorrow," Kiffin said. "I'll have to look at that when it happens."
Culpepper is anxious to get his first start in an Oakland uniform. That it could come against the Dolphins, a team that released him in July after he missed most of 2006 with a knee injury, is all the more enticing to the veteran quarterback.
"The thing is, I'm a Florida guy," Culpepper said. "Unfortunately, I didn't get a chance to play healthy in front of the people down there in Miami. I feel like now I get a chance to show them who I am healthy.
"Football-wise, we just want to get another win. But for me personally, I was there and it will be a little different in that fact. But as far as just going out and playing football, I just want to go out there and get a win."