Hooker... wasn't his guy. Heupel had no intention of playing someone who had not earned it.
I didn't get to watch practice either. But the portions we did see... he was not the most accurate, did not have the most arm strength, did not have a significant advantage in getting the ball off, and wasn't more accurate. The rumors circulated that it wasn't any better in the closed portions of practice. He just wasn't as good as the others.
To assume that Heupel had ANY sort of personal bias against Bailey is just foolish.