Peyton recently met with the Miami Dolphins and he's not going to sign with a team unless he feels it's the best fit for him to succeed.
The Dolphins with Brandon Marshall are much better than the Dolphins without Brandon Marshall, and much more enticing for Manning.
That leaves Davone Bess, Brain Hartline and Anthony Fasano as the next three receiving threats on the depth chart and no receivers on the roster having more than 550 receiving yards last season. Not exactly ideal receivers for Peyton to be throwing to.
Unless the Dolphins make moves for better receivers, I simply can't see Peyton taking his talents to South Beach.