He will not succeed at another position until he himself embraces the idea that he cannot play quarterback in the NFL.
By that I mean the fans and media will never leave it alone. They'll constantly clamor for him to play QB. He is the only one who can shut that down for good by coming out and saying "I am not, nor do I want to be, a quarterback in this league. But I want to be a football player. Moreover, I want to be a running back/fullback/tight end/whatever and will devote all my energies and my significant athletic ability to playing that position. Everyone who wants to see me play quarterback can go on YouTube and watch my games at Florida and with Denver, because I am not going to play quarterback ever again."
That is his only chance to succeed in the NFL at another position and keep the quarterback position from becoming a damn circus.