I've actually been thinking about this the last couple days and with all the noise everyone has been making about running the ball all the time, I've been figuring PA rollout, intended to be a mid-range pass (but Gray probably ends up keeping it himself for a short gain).
They definitely need to make teams in general (and USC in particular) respect that Gray can actually throw the ball too. I think opening with a pass makes that argument, and the play action to keep USC off-balance (which they'll need to do if they're playing to win...which I'm assuming Kill will be.)