A group of about 16 New England Patriots players knelt during the national anthem on Sunday, drawing a chorus of boos from the crowd.
The Patriots were playing against the Houston Texans in Foxboro, Massachusetts.
Tom Brady was notably standing during the anthem, interlocking arms with his teammates.
Some fans reported that there were boos before and after the national anthem—a sign that they were directing their ire at the players.
Meanwhile, almost the entire Pittsburgh Steelers team stayed in the locker room during the national anthem before their 1 p.m. ET kickoff against the Chicago Bears at Soldier Field.
“People shouldn’t have to choose. If a guy wants to go about his normal business and participate in the anthem, he shouldn’t be forced to choose sides. If a guy feels the need to do something, he shouldn’t be separated from his teammate who chooses not to.”
One player, Alejandro Villanueva, a veteran, stood for the national anthem outside the locker room tunnel.
“If a player wants the privilege of making millions of dollars in the NFL, or other leagues, he or she should not be allowed to disrespect our Great American Flag (or Country) and should stand for the National Anthem. If not, YOU'RE FIRED. Find something else to do!” he also tweeted later on Saturday.