Officers often carry their guns 24-7, even when they're off the job in case they come across a crisis or a threat.
But we've obtained an internal memo from the league. It limits permission to carry guns to law enforcement officers specifically assigned to work security at the games, or private security officers contracted for stadium protection.
The police union is disappointed.
"I understand they're screening a little bit more with metal detectors, but you know when we walk through city streets we're police officers, too," Union President Jeff Filler said.
"You never know what's gonna happen or when it's gonna happen."
The League Head of Security says that for each game, teams usually have about 250 armed uniformed officers. Plus hundreds of civilians.
"The likelihood there's a need for the use of deadly force by an off-duty officer is extremely remote," Jeffrey Miller said.
He also points out that an off-duty cop in the stands may be drinking, or won't know a stadium security plan.
The league has slowly increased security at stadiums in recent years, now even using metal detectors at gates. The league says a typical NFL game would have about 250 uniformed officers, and the NFL believes the chances of trouble requiring deadly force from off-duty officers in the stands are remote.