We'll hear that it's a must-win game, but that isn't true - 4 losses doesn't finish anyone's season.
I prefer to think of it as an opportunity. The team's low and a statement win could change the outlook dramatically (much like beating down the Cowboys last year did, but much bigger, as it would be Favre and Co.).
Realistically, if they don't get guys like Pickett, Neal and Matthews back, I don't know that it's possible. If those guys come back and you also can add someone like Harris, then the defense looks much more capable of getting to Favre and putting him on his butt. If they can do that, there's a real chance.
It's definitely possible, if a few guys can get healthy.