1) ... I'm not sure it even needs to be said. Slow Down Adrian Peterson.
I mean come on, I'm pretty sure everyone on the planet knows Adrian Peterson is the gear that makes this Vikings' offense work. Unfortunately, knowing that doesn't stop Peterson all by itself. Actually... ahem... stopping him is a good way to stop him. Not something that teams have proven able to do over his career, and certainly not this season (the Vikings do a good enough job of that themselves - heyo!).
On a more serious note, Adrian Peterson is pretty damn good. Five games into the season and he's averaging 99.6 yards per game with 6 TDs. That's only the beginning - in his career against the Bears (7 games) he's averaged 112.0 yards per game on the ground with 11 TDs and a 5.03 YPA. Now keep in mind he's going up against a current Bears team that hasn't shown itself to be as stout against the run as in prior years, with Matt Toeaina out and Anthony Adams so far not playing up to his billing.
Brian Urlacher and Lance Briggs will have to be the guys stepping up to stop the run if it isn't getting done at the line, like it has in years past.
2) Keep an eye on Percy Harvin
I know he's listed as questionable for the game, but if he plays, the Vikings love to line him up just about anywhere there's a position on the football field - although I don't think he's tried offensive line yet (though I'm pretty sure he'd be better than Frank Omiyale). He'll line up in the backfield as a running threat, he's a prime end-around/reverse target, and he's a very solid receiver in his own right. He also happens to be the second-leading rusher on the team (153 yards / 11.8 YPA). Take that, Toby Gerhart!
I like Harvin a lot. I'd really like to see what happens when he has a prime, not-so-over-the-hill quarterback trying to throw the ball - wait, no. No I wouldn't.
3) Where does the defensive line get its pressure from?
Silly question to ask, I know - first, we have to ask something along the lines of "HAS the line gotten any pressure lately?!" And the answer's pretty much "no." And if Peppers doesn't dress tomorrow, the one lineman that might command double teams just doesn't exist.
So that leads to... Will we get to see Corey Wootton get starter's snaps if he plays with his hand injury, or do we get more Nick Reed and Mario Addison ahead of him? How much time does Stephen Paea get in place of Toeaina, or will the Bears try to get more out of Amobi Okoye? At this point, I'd almost rather start seeing the other guys get a chance in limited time, because what we've seen the last four weeks just hasn't worked consistently enough.
I'm usually the last guy making reactionary changes, but I think this week, given the injuries, it's a perfect situation to see what a Paea can give the Bears in Toe's snaps instead of shifting over Okoye.