The NFL Players' Association announced on Tuesday that it has filed a grievance on behalf of the players challenging the league's controversial anthem policy, which was introduced in May.

"The union's claim is that this new policy, imposed by the NFL's governing body without consultation with the NFLPA, is inconsistent with the collective bargaining agreement and infringes on player rights," the NFLPA said in a statement. "In advance of our filing today, we proposed to the NFL to begin confidential discussions with the NFLPA Executive Committee to find a solution to this issue instead of immediately proceeding with litigation. The NFL has agreed to proceed with those discussions and we look forward to starting them soon."

The NFLPA raised similar points hours after the anthem policy was unveiled.

The NFL chose to not consult the union in the development of this new "policy." NFL players have shown their patriotism through their social activism, their community service, in support of our military and law enforcement and yes, through their protests to raise awareness about the issues they care about.

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.

Our union will review the new "policy" and challenge any aspect of it that is inconsistent with the collective bargaining agreement.

At issue: On May 23, NFL owners passed a resolution that allows players to remain in the locker room during the national anthem but those who are on the sidelines will be required to stand. Teams -- not players -- will be fined for any actions deemed disrespectful. In a statement, commissioner Roger Goodell said, "all league and team personnel shall stand," and added, "It was unfortunate that on-field protests created a false perception among many that thousands of NFL players were unpatriotic. This is not and was never the case." 

Goodell also outlined the expectations for the 2018 season:

The membership also strongly believes that:

1. All team and league personnel on the field shall stand and show respect for the flag and the Anthem.

2. The Game Operations Manual will be revised to remove the requirement that all players be on the field for the Anthem.

3. Personnel who choose not to stand for the Anthem may stay in the locker room or in a similar location off the field until after the Anthem has been performed.

4. A club will be fined by the League if its personnel are on the field and do not stand and show respect for the flag and the Anthem.

5. Each club may develop its own work rules, consistent with the above principles, regarding its personnel who do not stand and show respect for the flag and the Anthem.

6. The Commissioner will impose appropriate discipline on league personnel who do not stand and show respect for the flag and the Anthem.

Despite the NFL calling the new rule a "compromise," the NFLPA wasn't involved in helping fashion the new rule, something the NFLPA's George Atallah made clear at the time.

The rules change has given new life to a divisive issue that had faded from the headlines in recent months. Many players have spoken out against it, including Packers wide receiver Davante Adams.

"We're not out here holding signs, saying we don't care about the troops or we don't care about our country or whatever," he said last month. "It's a peaceful protest, and it's something as simple as people just expressing themselves and how they wanted to do it. It brought light to the situation, but at the same time, it's headed in a negative direction with people getting in trouble for it now. The league should've just stayed in their place where they were before and allowed people to do whatever it was that they were doing."