I think the most reasonable scenario is:
1) He's gay
2) His football teammates were always wondering why he wasn't out bangin' chicks around campus like the rest of them
3) He makes up some lame excuse about a "girlfriend back home"
4) As they press for more details he makes up more stories about visiting her in california or Hawaii when he goes back home. No one in Indiana can really confirm or deny any of this as they're too damn far away from Cali/Hawaii to really know.
5) He gets a handful of close friends(probably not on the football team) to help him perpetuate the hoax, they know he's gay and they want to help not cause a rift with the team
6) Shit gets blown WAY out of proportion when media starts to pick up details about his "girlfriend back home", and he's too damn embarassed at that point to come clean, so he just goes with it...and now here we are
Being gay is a huge no-no in the Morman religion, and isn't accepted within the culture of a football team either, nor very accepted at a Catholic university. The 3 main influential factors in his life have huge problems with his lifestyle, so he went to extreme lengths to hide it.