I don't think you understand what malice means in a legal context.
Malice is defined as desire to inflict harm but in a legal context, Vilma doesn't have to go that far to prove "malice" in a defamation suit.
In a legal context malice means knowledge that it was false or "reckless disregard of whether it was false or not"
Depending on the eivdence the league has, and the actions taken by Goodell weighed against that evidence reckless disregard could be a standard that Vilma may meet.
Unlikely Vilma meets such a standard, but that's not the purpose of this suit anyway