I also think the timing is interesting. The Lions were on a big upswing trajectory; going into this year, they looked like a real Super Bowl possibility. Then, they got eliminated - so maybe he is looking at it and thinking, what if my stock doesn't go up from here? Maybe he or someone has also heard some of the criticism on that gadget play or other plays too. There has been some blowback, maybe some very minor damage to the rep. Brady, who reportedly was pushing him for the Raiders position, witnessed the trick play firsthand and was unimpressed after all.
It's interesting how dominoes sometimes fall.