to the fact that BYU's defense is holding their opponents to 120 yards/game on the ground. As a coach, you have to plan around your strengths. unfortunately, BYU doesn't have too many weaknesses to break down a defense. You might get lucky with a long play here and there. But, BYU's defense is no longer a bend-don't-break defense.
BYU will stack the box and force OK-State to pass. And to that, I say, good luck!