Peyton Manning’s new deal has a no-trade clause
Even without a no-trade clause, it’s unlikely that any team would trade for Peyton Manning if he didn’t want to play for that team. Still, Peyton asked for and received a commitment that the Broncos won’t, and can’t, ship him to another city, in 2015.
Two guesses as to the reason behind this: either Peyton doesn't entirely trust John Elway and thought a trade might be possible, or the NFLPA wanted to be sure that Manning got something in exchange for taking a pay cut for the first time. Over the years, it's often been suggested that the union wouldn't want any of its marquee players taking pay cuts.