Enough is enough. Juan Castillo was in over his head when the Philadelphia Eagles hired him as defensive coordinator, and he still is. Maybe he's slipped free of that block of cement that was holding him at the bottom of the river, but he hasn't broken the surface yet and the Eagles are running out of time.

Yes, the Eagles had been having a great defensive year. Yes, they were having one of their most impressive performances in memory against the Lions yesterday... until it all fell apart.

The Eagles didn't just blow a 10 point lead when kicking the ball away with 5:18 left, they also gave up 17 fourth quarter points and three more in overtime after allowing just six through three quarters.  They've only given up 20 points in a game after allowing six through three quarters one other time in team history - in 1985 against the Vikings.

Why the collapse? The Eagles changed what they were doing defensively. They found something that worked extremely well, then inexplicably got away from it.

Through the first three quarters, superstar wide receiver Calvin Johnson had just one catch for 28 yards, mostly covered by cornerback Nnamdi Asomugha.

Read more on what Castillo changed and why it should be the final straw.

Ryan Messick covers the Eagles for 97.3 ESPN FM.  Follow him on Twitter.