When you consider a coordinator change in the middle of a head coaching tenure, you need to find a candidate that not only believes in the head coach, but his scheme as well.
Several coordinators change things up if they plan to take over a side of the ball that the head coach has little interest in, but coordinators that assist in preaching the main man's message typically have to buy into the boss's ideals.
Of all of the potential external candidates for the Jacksonville Jaguars open defensive coordinator position, soon-to-be former Philadelphia Eagles defensive coordinator Billy Davis makes the most sense.