Yeah, the NFL itself has some sort of status as a confederation of individual businesses (the 32 franchises) and in and of itself is a non-profit, though not in the traditional churches-schools-museums 501c(3) vein. It's actually a 501c(6). Forbes had a good write up on it.
Definition of a 501c6:
Business leagues, chambers of commerce, real-estate boards, boards of trade, or professional football leagues (whether or not administering a pension fund for football players), not organized for profit and no part of the net earnings of which inures to the benefit of any private shareholder or individual.
http://www.forbes.com/sites/peterjreilly/2013/06/01/nfl-as-tax-exempt-less-than-meets-the-eye/