She saw him wearing a BYU shirt while he was training to earn a roster spot somewhere.

Wife: "Did you go to BYU? I went there a while back."
Leslie: "Yes! I played football there."
Wife: "Oh, sorry. I can't cheer for BYU football because they always lose."
Leslie: (confused look)
Wife: "Well, um, I mean..." (tries to backtrack and gets embarrassed while he just starts laughing). "Anyway, best of luck and I hope you make the team."

At least he was representing the Y post-graduation.