Good point Charlie.
I personally hate the way this is playing out. No matter what we think, human nature will come into play here. The first time the starter is in game action and makes a bad throw/decision/read, he'll begin to look over his shoulder and press. It's only a matter of time. It's unnecessary. Give Brooks the opportunity he deserves, make it clear that he's the guy, and let him focus on production rather than keeping his job. If Nixon is needed, have him prepare so that he can be ready.
I think we're making this harder than it has to be. But hell, Hud might be playing media games with UK, so...