Don't count out Brett Favre just yet, although his coach admits it would "tough" to see the 41-year-old quarterback playing Sunday.
Frazier wouldn't specify Favre's status in the NFL's medical protocol for concussed players, but he told ESPN: "I don't think he's going to make it. It's going to be tough."
If Favre can't go against Detroit, rookie quarterback Joe Webb is prepared to make his second career start for Minnesota.
Favre didn't speak to reporters this week, but Frazier on Friday described the quarterback's attitude as positive. As teammates stretched and warmed up before practice that day, Favre did a little dancing on the side while music by Michael Jackson and Vanilla Ice blared on the speakers. Favre wore his red non-contact jersey, but he didn't have a helmet on and didn't participate in any drills.
Favre has started in 13 games for the Vikings this season, passing for 2,509 yards and 11 touchdowns with 19 interceptions and five lost fumbles during a problematic campaign that has yielded a 69.9 rating in his 20th -- and, he claims for now, final -- season.
The Associated Press contributed to this report.