I could be WAY off here, but i don't think that is the case. He is being promoted to OC from a RB coach. Unless he is getting a much higher salary as a position coach, Its hard for me to see him going elsewhere at this point.
Dorsey was a guy with NFL experience and went back to the NFL. Riley may well be an rising star, but I don't think he has done enough yet to be in that high demand. Even at a smaller salary, an OC role is going to get him much more experience and attention at App than a QB coach or TE coach even at bigger schools