UPDATE: When the new national anthem policy was first announced in May, President Trump said he supported the measure, per ProFootballTalk:

"I think that's good," Trump said on Fox and Friends. "I don't think people should be staying in locker rooms, but still I think it's good. You have to stand proudly for the national anthem or you shouldn't be playing, you shouldn't be there, maybe you shouldn't be in the country. You have to stand proudly for the national anthem and the NFL owners did the right thing if that's what they've done."

President Donald Trump is once again taking aim at the NFL, this time for the league's new national anthem policy.

In May, partly in response to Trump's repeated protests, NFL owners announced a new policy for the 2018 season.

All team and league personnel, including players, who are on the field for the pregame will be required to stand and "show respect" for the flag and the anthem under terms of the policy.

But it no longer is required that all players on the field for the anthem, meaning players who wish to protest can stay inside the locker room or off the field. The protests typically are meant to bring awareness to social injustices and/or police brutality.

The NFL can fine teams -- not individuals -- whose personnel violate the policy, but the teams have the authority to develop their own set of rules within the framework of the NFL policy.

Trump tore into the league for its new anthem policy during a campaign-style rally on Thursday in Montana, per ProFootballTalk:

"Look, I don't want to cause controversy. . . . But how about they pass this stupid thing. You don't have to do this anymore. If you don't respect the flag, or if you don't like the country, or whatever it is. Just go into the locker room. . . . I think in many respects, that's worse. Isn't that worse than not standing? I think that's worse. . . . I actually think in many ways it's worse."

Trump also took a shot at NFL Commissioner Roger Goodell:

"I heard this thing, they were so happy, the owners," Trump said. "This Commissioner, where this guy comes from I have no [idea]. They're paying him $40 million a year, and their ratings are down 20 percent. But you know why their ratings are down? Yes, the flag. But they're also down because people find politics -- in other words, hitting Trump, incorrectly, but hitting Trump -- they find that to be much tougher, meaner, and more interesting than watching a football game. They actually do. And they're watching the cable networks instead of watching football."

That Trump is displeased with the NFL is no shocker. Last month, he cancelled a trip to the White House for the Philadelphia Eagles to celebrate their 41-33 victory over the New England Patriots in Super Bowl LII.

Mike Rosenstein may be reached at mrosenstein@njadvancemedia.com. Follow him on Twitter @rosenstein73. Find NJ.com on Facebook.