It isn't easy to rebuild a football franchise. That is exactly what Miami Dolphins owner Stephen Ross has tasked Jon-Eric Sullivan with doing. NFL teams don't typically turnover their executives unless the losing is so bad it can't be avoided.
In Miami, it was deeper than losing. It was about defining a franchise. Chris Grier didn't lose his job because he was horrible at drafting quality players, or because he couldn't manage the salary cap, or because he couldn't keep his draft picks four years later. It was all of it, and that is what Sullivan has to fix.