No, there is no specific contract. We can wear alternates and throwbacks whenever we want. I think they were only do it once a game because the stupid *** fan base here FREAKS OUT at anything new and exciting. :-D
I totally agree though that the alternates have been very hit and miss. The Northwestern ones ruled, and a close second would be those black and white UCLA ones. The others ranged from "meh" to downright ugly. The good news is, Adidas hired a bunch of the ex-Nike designers a few years back, and the quality of their design output has generally risen dramatically since then. So, I hope we do an alternate this year, and it would be pretty sweet to do it more than once. I'm sure Frost would be in favor of it, coming from friggin' Oregon, and at UCF they wore different uniforms a few times.