DENVER — Denver Broncos linebacker Brandon Marshall knelt during the national anthem prior to the NFL’s season-opening game Thursday night against the Carolina Panthers.

Marshall dropped to one knee at the far right side of the line of Broncos players along their sideline for the playing of the anthem. All of Carolina’s players stood for the anthem.

San Francisco 49ers quarterback Colin Kaepernick sparked a national debate when he refused to stand for the anthem during the preseason as a protest of the treatment of African Americans in the United States.

Marshall, who was a college teammate of Kaepernick at Nevada, previously had expressed support for the 49ers quarterback’s protest.

“I support Colin,” Marshall told the Denver Post late last month. “I support Kaep. I understand where he’s coming from. I definitely see what he’s saying. I support him on that. I’m not mad at him for that. Some people are bashing him on the Internet, but I’m not bashing him at all. I support him.”

The Broncos said in a written statement: “While we encourage members of our organization to stand during the National Anthem, we understand and respect it being a personal decision.”

San Francisco safety Eric Reid and Seattle Seahawks cornerback Jeremy Lane later joined Kaepernick’s protest. So, too, did women’s professional soccer player Megan Rapinoe, leading the Washington Spirit to play the anthem with the players still in their locker rooms prior to a game involving Rapinoe.