Let's face it for the Bears to knock off the Indianapolis Colts on the opening game of the season in their brand new stadium they have to get pressue on Peyton Manning.  But that isn't all.  They have to get that pressure with their front four.  With the arsenal of WRs and TEs, Manning has at his disposal the Bears can't afford to be coming hard too often or they will be giving up some big plays.

Colts center Jeff Saturday has a strained MCL:

...if Jeff Saturday opts to not have surgery on his strained MCL, he's back in 6 weeks, maybe. If he does opt for surgery, he's back in 11 weeks.

We know now that Peyton Manning is going to play, but there will be some effect.  Don't know how rusty or gentle he will be, but having a backup center with Tommie Harris pushing up the middle could cause some issues for the Colts.