I think this is a US/British English distinction, since saying "The New York Mets" or "The Dallas Cowboys" is the norm, but never "The Manchester United" or "The Rangers" (despite being a plural).
Come to think of it, does any NFL team not end in a plural?
Stanford Cardinal, Norte Dame Fighting Irish, Illinois Illini, Syracuse Orange, the two Wolf Pack (NC State and Nevada), and I cannot think of a seventh school.
If I can’t use colors then I guess Syracuse doesn’t count.
Come to think of it, does any NFL team not end in a plural?