Got this from someone and this was nice as it is really a good explanation I thought: " Agree, my take was that Mercer took one thing away defensively by pinching a D tackle and with some backside stunts playing too tight. I assume GQ saw it and still ran it to keep them in that alignment so he could pop it and also eliminate their LB’s ability to cover pass protection and with play action they were non existent. Wouldn’t worry we ran it up the middle better against FBS talent who had better (more balanced) schemes. I love it when they overcommit to one element. Makes play calling fun for good guys"