I'm not clear on what Rogers' status is. Is he enrolled, not enrolled, on the team, not on the team? A professional athlete has to be extremely careful of getting involved in any way with college athletes. See Deion Sanders/Dez Bryant. All of it is against one rule or another.
It's just a tricky situation for all involved so that is the only reason, I'm sure, that he wouldn't be willing. Plus, coaches don't particularly care for outside influences. It diminishes their role in the situation. If there's not mutual respect there to begin with, any outside force would certainly make that worse.
Now if a coach brings a former UT athlete in to talk to the team as a whole, that's a different story. But that has not ever happened with Arian.