Fantasy football is dealing in statistics. Using a persons name in your game implies they endorse your game, the players associations manage this stuff pretty closely.
I think there were court cases on infringement around thirty years ago, when games were being made where they'd just license Shaq or Ken Griffey Jr and the rest of the names would be fake.
I am sure that argument would be made, but I don’t think customers actually think that. Especially if the game makes it clear it’s unofficial.