This guy was already a QB on the decline. His last year he had a QB rating of 91.9, which sounds good, but was also his lowest since 2002. You combine that with being in a new system and new players. And I expect that brings it down. You would like to compare Favre and Manning and show Favre having a resurgence, but he did so when he was combined with great weapons, specifically Adrian Peterson. McGahee isn't Adrian Peterson, he is closer to Addai. Decker isn't Reggie Wayne. Thomas isn't Marvin Harrison.