When the Cowboys made the decision to move on from Jason Garrett, one of the things that was most clear was that their defense needed big changes. Under Rod Marinelli and Kris Richard, the defense had become far too predictable and thus too easy to exploit. It was a given that their defensive linemen were always going to shoot the gap and their defensive backs were always going to play Cover 3, so opposing offenses built their run games around trap blocks and their pass games around Cover 3 beaters.
But it wasn’t just that the defensive scheme was predictable. The larger issue was that the front and back ends were rarely in sync. Marinelli’s Tampa 2 roots relied on penetrating defensive linemen with linebackers in the shallow middle of the field to contend with the run; Richard’s Legion of Boom defense featured bigger bodies in the trenches that required less linebackers in the box and allowed them to cover the shallow zones on the edges in Cover 3.