(Reuters) - Denver Broncos linebacker Brandon Marshall became the latest athlete to kneel during the U.S. national anthem in a protest against social injustice before his team's game against the Carolina Panthers on Thursday.

Marshall, following in the path of San Francisco 49ers quarterback Colin Kaepernick, knelt on the sideline before the anthem began, and remained in that position while his team mates stood to his left.

"The message is I'm against social injustice," Marshall said after the game, according to NFL.com. "I'm not against the military or police or America at all. I'm against social injustice and I feel like this was the right thing to do."

Marshall, who is black, is the third NFL player to not stand during the national anthem since Kaepernick began his sideline protest against racial injustice and police brutality.

Kaepernick's teammate Eric Reid joined in the protest during the 49ers' pre-season finale last week while Seattle Seahawks cornerback Jeremy Lane sat on the bench last week against the Oakland Raiders.

The NFL's opening week resumes Sunday with 13 games and some players, including Seattle receiver Doug Baldwin and defensive end Cliff Avril have said they are considering not standing during the national anthem before their game against Miami.

Many Americans saw Kaepernick's gesture as a sign of disrespect to the flag and criticism was widespread, but he has also been supported by several fellow athletes, including Megan Rapinoe, a white soccer player who knelt before her game on Sunday.

"While we encourage members of our organization to stand during the national anthem, we understand and respect it being a personal decision," the Broncos said in a statement.

Marshall, who was Denver's second-leading tackler during their run to a Super Bowl title last season and a teammate of Kaepernick at the University of Nevada, said last week that he supported Kaepernick's actions.

"Brandon is a great kid. He is a leader of this team," Broncos head coach Gary Kubiak said after the game. "I believe in our guys and I believe in them wholeheartedly. We move forward."

The use of force by police against African-Americans in cities such as Baltimore, New York, and Ferguson, Missouri, has sparked periodic and sometimes destructive protests in the past two years and prompted the rise of the Black Lives Matter movement.

Kaepernick led San Francisco to a Super Bowl berth in 2013 but has since been demoted to backup. He played in nine games last season and had more turnovers than touchdowns.

But since he began his protests during the preseason Kaepernick's jersey has become the top-selling jersey on the National Football League's official online store.

(Reporting by Brendan O'Brien in Milwaukee; Editing by Simon Cameron-Moore)