I would think that coordinators know the opposite side of the ball just as well as it would be hard to do their job if they didn't. How can a DC stay one step ahead of an offense if they don't understand scheme, play calling, and aspects of offenses.Barry Alvarez was a career defensive coach and was ND’s D coordinator when Donna Shalala and Pat Richter hired him at Wisconsin, where his teams were known for their offensive approach (specifically, their power running game). Plenty of D coaches can and do become excellent offensive stewards.