I think that fans typically are fans of schools.

Players, on the other hand, don't necessarily look at schools as much as coaches, their systems, their ability to progress, and their ability to win. If I was an athlete (I'm far from one) and I was getting attention from a coach of a team I was a fan of (BYU) as well as a coach that gives me good attention, notes to improve, and a system where I'd succeed (even if it's at a school that I don't have any ties to) then I would probably go to the coach that has proven to me that I'll succeed. That relationship matters more to me than what color my jersey is.