NFL referees will issue a 15-yard penalty for an illegal facemask on the field -- but now fans in the stands have to be mindful of a new face-mask rule as league officials prepare to start the first season since the coronavirus outbreak.

“For those wondering, yes, it is league-wide,” NFL spokesman Brian McCarthy tweeted Wednesday. “Fans at NFL games this season will be required to wear face coverings.”

Traditionally in football, a facemask has been defined as controlling the mask of another player.

“No player shall grasp, control, twist, turn, push, or pull the facemask of an opponent in any direction,” the NFL rules state. “If a player grasps an opponent’s facemask, he must immediately release it. If he does not immediately release it and controls his opponent, it is a foul.”

Now fans will be required to wear facial coverings if they attend any NFL games in person this season.

GIANTS AND JETS FANS WON'T BE ALLOWED AT GAMES

But the rule may not even matter for fans of some teams -- with the New York Jets and Giants jointly announcing earlier this week that no fans will be allowed in MetLife Stadium “until further notice.”

They made the statement after New Jersey Gov. Phil Murphy banned outdoor crowds of more than 500 during the coronavirus crisis. MetLife Stadium is in New Jersey, not New York.

And the Atlanta Falcons have announced they’ll host only partial capacity crowds -- 10,000 to 20,000 fans in their 70,000-seat Mercedes-Benz Stadium this fall, CBS Sports reported.

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As for on-field use, the NFL unveiled a prototype face shield last week that players can attach to their helmets. It was designed by Oakley, which already makes the visors that some players wear.

This image provided by Oakley shows sketches of the new face shield designed by Oakley. With NFL training camps set to start at the end of the month, the league believes it is closer to one answer when it comes to player safety in the midst of the coronavirus pandemic. Face shields for the players' helmets. (Oakley via AP)

This image provided by Oakley shows sketches of the new face shield designed by Oakley. With NFL training camps set to start at the end of the month, the league believes it is closer to one answer when it comes to player safety in the midst of the coronavirus pandemic. Face shields for the players' helmets. (Oakley via AP)

But the idea might not be popular with players, according to Yahoo! Sports: Houston Texans defensive end J.J. Watt has already said he would sit out the season if the league were to mandate face coverings.

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For fans who can make it to games this season, or for anyone who wants to support their team while wearing a mask somewhere else, vendors are already selling team-logo face coverings.