The NFL has adopted a new policy that will punish players who kneel on the field during the national anthem.

The Associated Press reports that NFL owners approved the new rules during their annual meetings this week. The new policy will allow players to stay inside the locker room during the anthem but states that they must stand if they are present on the field or sideline.

The rule change comes after a contentious 2017 season in which numerous players on various teams chose to kneel during the anthem as a sign of protest. The demonstrations led to a huge amount of controversy among fans, with several choosing to boycott the league as a result.

Under the change, individual teams would have the power to set their own policies. If a player does choose to kneel on the sideline, his team could potentially fine him and the league could fine the team.

The NFL Players Association says it was not consulted over the rule change and that it plans to review the policy.