But the Players Union says they were not even consulted about the change and may fight it.
"We want people to be respectful of the national anthem". That's something that we think we owe.
He tweeted out a statement on Wednesday night criticizing the NFL's decision, accusing the National Football League owners - which voted unanimously in favor of the new policy, including Eagles owner Jeffrey Lurie - of thwarting the players' "constitutional rights to express themselves and use our platform to draw attention to social injustices like racial inequality in our country".
The owners spent several hours addressing the contentious issue - which has reached all the way to the White House.
Philadelphia Eagles defensive end Chris Long accused the league of bowing to President Trump, who whipped up opposition a year ago to the take-a-knee protests, adding that the owners "don't love America more than the players". Perhaps it's payback for being deposed last week by Colin Kaepernick's lawyers in the former QB's collusion case against the NFL.
The NFL Players Association, which was not included in league discussions on how to handle the anthem issue, threatened to challenge the policy if it was deemed a violation of its agreement with the league. I don't want to come down on them like a ton of bricks, and I won't.
"The vote by NFL club CEOs today contradicts the statements made to our player leadership by Commissioner Roger Goodell and the Chairman of the NFL's Management Council John Mara about the principles, values and patriotism of our League".
The NFL was reportedly considering whether to assess a 15-yard penalty against any player who took a knee or conducted any other protest during the anthem. Those owners added that, if players and others choose to take the field for the playing of the National Anthem, they can't sit or kneel or do anything else that doesn't involve standing - or else.
New York Jets co-owner Christopher Johnson will pay any fines his players might be subjected to as part of the NFL's new national anthem policy. I think the people pushed it forward. It then became more heated last fall following comments from Trump. "I don't think people should be staying in the locker rooms, but still I think it's good".
The new policy says players must "show respect" as they stand, but not does not silence them completely.
In the statement, National Football League commissioner Roger Goodell spoke on behalf of all 32 organisations, detailing six guidelines that are expected of team staff and players in order to "show respect for the flag and the anthem".
"I am not going to stand up to show pride in a flag for a country that oppresses black people and people of color", Kaepernick said.