It is hard to say Peyton Manning should be the MVP and Comeback Player of the year when Adrian Peterson could also be regarded in both conversations. There is, however, two reasons reason I think he should get the nod for both these prestigious awards. In the case of Adrian Peterson, the healing process of his injury was astronomical. The production that followed was then astounding and unheard of. In the case of Manning, location and duration are what convinced me he should get both.
First off, he came to a brand new team in a brand new location. He transitioned to a team that was in a far different area of the country in a different altitude and basic state of mind. He went from an indoor stadium to an outdoor one, which presents all of the elements Manning historically was not used to nor did well in. A place that is open and can be cold and snowy like all the games in Boston he would like to forget. All of this could be enough to drastically change a person or their numbers, but none of that happened and the wins continued. If anything it appeared he has been trying to conquer his fears.
Duration has been the other impressive thing that has baffled me personally. Manning played with few players on the team other then Brandon Stokley and Jacob Tamme. Tamme was his last tight end he had in Indianapolis, but they only were together but a year when Dallas Clark went down to injury. Stokley, on the other hand, last played with Manning in 2006. These two players were the only thing familiar to Manning who had to come in and lead immediately. At first it was not as smooth as one would hope, but that was expected. The ten weeks Denver have one consecutively after a 2-3 start, however, is something many probably would not have expected.