Peyton Manning has the ability to audible to a number of plays at the line of scrimmage. Typically, he will get to the line of scrimmage, call out his adjustments, and move forward from there. Baltimore will likely use a scheme in which, they will not show Manning their exact coverage on defense until very late in the play clock.
I have begun calling this "The Manning Effect" on defenses. He has changed the way in which the quarterback position is used on the field.
During his 48 touchdown-pass season, he was virtually unstoppable. Various defenses were used, from a two-man front to loading nine in-the-box, Manning diffused everything that was thrown at him. His ability to diagnose pressure and audible to the correct formation or play has been essentially un-matched by any other player in the NFL.
Since, teams have decided not to show him whether they are playing man or zone until very late in the play clock. This has eliminated his ability to inform his teammates of any new plays or hot routes. This also limits what the defense can do also. Therefore, if Ray Lewis calls just a basic Tampa-Two defense, odds are, they will run that play.
If Manning calls the right play from the start, Baltimore will have a tough time adjusting because if they show him too much, he will check into the perfect play. This effect is the reason the Colts are virtually unstoppable on offense when all things are clicking. When they get in trouble, it's when the defensive coordinator simply been guessing right.
The two Indianapolis losses can really be discounted as losses because Manning was pulled in the second-half of their 15th game. The way the Colts have played all season, they are really unlikely to breakaway from a team on the scoreboard because of this "Manning Effect" on the defense. He is so unlikely to make a bad decision of late, that defenses are just playing the bend-don't-break style.
Coordinators are hoping that roughly 40 percent of the plays they call on defense are right, and in-turn Manning will giveaway two passes during the game. I believe the key to a Ravens victory tonight is going to be two-Peyton Manning turnovers. If they can control the pace on the ground and force two interceptions, than the Ravens have a legit shot of winning in Indianapolis.
If early in the game, you see Manning coming to the line of scrimmage, and the defense giving up 10-yard chunks every play, than it's going to be a real long night for Ravens fans.