Firing Coordinators midseason usually opens the door for the HC to get the boot as well.
Texas DC Manny Diaz was fired today...and Diaz is a pretty good DC, IMO.
That's called a knee jerk reaction. I've gotta a really strong feeling that Texas' fall has a lot more to it than just the DC (maybe they have the same strength and conditioning that Coach Chizik modeled his S&C around).