I have no idea if Peyton Manning's health will allow him to play another year in the NFL. Let's assume he gets a clean bill of health and wants to play another year or two. I have no idea if the Colts want him back or will cut ties with him in March. Let's assume that firing the Polians and Caldwell signals that the Colts will start from scratch and rebuild with Luck. That makes a heathly Peyton Manning a free agent come March. What team will sign him?
It won't be Washington. Team's a mess plus I don't think he wants the drama of playing Eli twice a year.
It won't be Miami. Team's a mess, new coach plus I don't think he wants to play Brady twice a year unless he has the team behind him to beat Brady.
It won't be New York Jets. Team's a disaster in waiting, Sanchez situation is messy and again I don't think he wants to go up against Brady twice a year unless he's got a great team behind him.
There is a perfect spot for him. San Francisco. Alex Smith is a free agent. Don't resign him. He's Fitzpatrick except he doesn't throw as many picks. You've got arguably the best defense in the NFL, an ok but hopefully young and improving O-Line, a potentially great tight end, and a really good running game. Pick up one of the free agent wideouts (V. Jackson, D. Jackson, Bowe or S. Johnson), draft a wide-out no.1 and you are absolutely set to challenge for a Super Bowl win. You're not even screwing up your "future". SF spent a #2 on Colin Kaeperick last year. Start Peyton for two years while you continue to groom him a la Rogers. It makes too much sense not to happen.