The NFL is reportedly considering punishing players who kneel in protest of police brutality during the national anthem ahead of games.

At a Tuesday meeting in Atlanta, NFL owners weighed the possibility of introducing 15-yard penalties for players who kneel during the anthem, Sports Illustrated reports. As part of the rule, home teams can decide whether both teams will come out of the locker room during the national anthem — penalties can be handed out for any player that kneels.

Several NFL players have taken a knee during the national anthem over the last two seasons as part of an effort to raise awareness of police brutality and racial inequality. Colin Kaepernick, known for kicking off the protest in 2016, has sued the NFL along with Eric Reid, saying league teams have worked together to keep the players unsigned. Both are currently free agents.

Kaepernick’s kneeling prompted many other players to kneel over the 2016 and 2017 football seasons. The national anthem protests ramped up significantly during the 2017 season, after President Donald Trump slammed players who kneeled, calling anyone who did so a “son of a bitch” who deserved to be fired.