Miami Dolphins players who protest on the field during the national anthem could be suspended for up to four games under a team policy issued this week.

The “Proper Anthem Conduct” section is just one sentence in a nine-page discipline document provided to The Associated Press by a person familiar with the policy who insisted on anonymity because the document is not public. It classifies anthem protests under a large list of “conduct detrimental to the club,” all of which could lead to a paid or unpaid suspension, a fine or both.

Miami’s anthem policy comes after the NFL decided in May that teams would be fined if players didn’t stand during “The Star-Spangled Banner” while on the field. The league left it up to teams on how to punish players. None of the team policies have been made public.

The NFL rule forbids players from sitting or taking a knee if they are on the field or sidelines during the national anthem, but allows them to stay in the locker room if they wish. The new league rules were challenged this month in a grievance by the players union.