I don't understand what's so difficult to understand about AJ gets the nod if Greg gets hurt. It's pretty simple to me.
As to AJ's size. He's already got 15, maybe 20lbs on Brodie. And, he's also a good two and a half inches taller than Brodie. The kid is filling out well for someone his age.
I don't disagree that Star has looked good when he's played against North Texas. He was 9 for 13 in that game. Hell, Greg was 13 for 15 in that game.
But, all you've seen in the other contest is Star handing the ball off to a running back.