Understand, Marinelli doesn’t like to blitz. Abhors it. He wants to use a four-man rush to harass the quarterback and drop seven into coverage because he believes that’s the best way to play pass defense. The problem, of course, is the Cowboys’ pass rush has been useless much of the season.
That means quarterbacks have more time to go through their progressions and find open receivers. Marinelli changed his tactics against Washington because the Cowboys needed to enhance their pass rush, and they believed Washington would have difficulty handling the blitz.