I've had this thought and pseudo-concern, but when you think about it, is there much of a successful history of "having the next head coach on staff"? Belichick wasn't on the Patriots staff before he took the job. Tomlin wasn't on Pittsburgh's staff. Jason Garrett is about the only coach in waiting situation that I am aware of and is he all that successful? Jim Caldwell did it, but didn't last. That's very true. Belichick also didn't really succeed at the Jets (he had been at the Patriots in 1996, prior to taking HC job after leaving NY). iirc, the Jets named Belichick their coach and he spurned them for the open NE job. He was with the Jets, promoted as an internal candidate when Parcells left, then bolted a day later.