Playing without Barnett all year and without McDaniel for a large amount of time has not helped.
We have also played 4 really good offenses the past 4 games.
Pretty much this, although OU's offense is not as good as we made them look. For whatever reason, our D has always taken a nose dive when our star safety goes down (which is, like, every year the past few seasons it seems).
Edit: also, bad offense.