Could be a combination of it all. Perry has an audible option but elects to use it in a situation he shouldn't have; Harley runs the route on the audible to the wrong side of the safety; Perry forces it to his boy anyhow because that's what he mentally committed to at the time he audibled and it leads to a pick; CMR loses his sh-t at the realization that this is the exact type of sh-t that happens when you aren't committed enough to learning and yanks him for his senior.
Makes a whole lot more sense than this idiotic "Richt just wants to get paid and doesnt care if we win" bullsh-t that's been spewed on here all afternoon. And if that scenario is true, its probably just a microcosm of a lot more of that kind of sh-t thats been going on behind the curtains that us fans are not privy to.
Richt isnt just blindly dedicated to Rosier or he would never have benched him for Perry, especially coming off a good game vs Toledo. He knows Rosier is limited, but its starting to look clear that his only other options are a knuckle head, a basket case and a potential talent who is still too green.