Most offenses seem to be taking a hard look at the Broncos' nickel package (five defensive backs) because of where Champ Bailey is. Against the Chargers, for example, Bailey matched up on San Diego wide receiver Vincent Jackson when the Broncos were in base defense, no matter where Jackson lined up.
However, when the Broncos went to the nickel, that moved Bailey into an inside position, where he covers the third receiver, no matter who it may be. Defenses have done this with the best cornerback all over the league because quarterbacks go to that slot receiver so often, but when the Broncos do it, quarterbacks are looking outside, especially with a chance to score, because Bailey isn't there.
Brandon Marshall will probably see plenty of Bailey on Sunday, though it sounds like Bailey will continue to play in the slot on third down.