Preseason games can occasionally get a little bit charged, because it's early game action, you've got young players trying to prove themselves, and tempers flare up. The NFL has recognized that and is apparently putting its massive, money-smeared foot down.
NFL exec @TroyVincent23 sent a memo to teams reminding them the prohibition on fighting during games will be a point of emphasis. Posting.
— Ian Rapoport (@RapSheet) August 14, 2015
It's not clear what kind of punishment might come from this, but the NFL has been particularly keen on cracking down on dumb penalties and fighting, which is one of the few enforcement actions the league has taken that I haven't been appalled by.