I've already heard comments made about the fact that the Saints are going to "go to man coverage" on Rex, which is something he hasn't seen much this season.
My response to this is: "Why?"
The entire secondary has struggled against the big play, and you're facing a young QB who has really struggled at times this season.
"Football sense" suggests that you play more of a zone, take away that deep ball (even using something of a cover 2 or 3 effect) and make the inconsistent Grossman have to be perfect to beat you.
I'd rather force the Bears to have to go 8-12 plays a drive--and make the perfect throws, blocks, and catches necessary to complete such drives---than give Rex and his big arm a few shots down the field.
If you take away the deep ball from Grossman, make them eat up clock to score, and pound McCallister-Karney-Bush on 30-40 carries, I don't see how the Saints lose (assuming no big turnovers and such). The more responsibility you place on the QB's shoulders, by forcing him to manage multiple long drives, the better---I think it's safe to say the All-Pro QB who has thrown only 1 INT the last 6 games is going to get the better of that matchup every time.
The Saints are physical enough to beat the Bears playing "Bear football"---eat up that clock, etc.