based on what he's done so far this season. He knows that most teams that have successfully beaten his team have stacked the box and put pressure on his inexperienced QB. That's football 101. He knows thoroughly that BYU has seen that blueprint. If he doesn't do anything significantly different, then he's not the coach he once was.
That's what would keep me up at night if I were a BYU coach. How you successfully react to what you didn't scheme for.