All plays are reviewed upstairs, but there was nothing to overturn. He went to the ground in the process of making the catch, and the ball ended up on the ground between his legs. It was, straight up, an incomplete pass.
Wrong. He had possession as his butt hit the turf, ball came out shortly after. Therefore, down by contact. As an aside, the catch in the back of the endzone by OU (before the kicker's TD) was also a TD; his feet were down, ball in receiver's possession. As I said earlier, worst officiating by far I've seen all year. Both sides got screwed repeatedly.