"The message is I'm against social injustice," Marshall said. "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.
"I feel like this is the right platform. This is our only platform to really be heard," Marshall continued. "I feel like a lot of times people want us to just shut up and entertain them, shut up and play football. But we have voices as well. We're actually educated individuals that went to college. So when we have an opinion and we speak it, I feel like a lot of people bash us for what we have to say."
Marshall is the third player to not stand during the national anthem since San Francisco 49ers quarterback Colin Kaepernick revealed last month that he was protesting against social injustice against African-Americans and other minorities in the United States by not standing for the anthem. Niners teammate Eric Reid joined Kaepernick in not standing during the team's preseason finale and Seattle Seahawks cornerback Jeremy Lane sat on the bench last week against the Oakland Raiders.
Marshall and Kaepernick were college teammates at Nevada and Marshall said he wanted to show his support for the quarterback's protest. He added that he understands some people aren't going to agree with his decision.
"I did it and I don't regret it," said Marshall, adding that he plans to donate money to military veterans. "I knew what territory it came with, and I decided to do it."
NFL Network's James Palmer obtained this statement from the Broncos regarding Marshall: "While we encourage members of our organization to stand during the national anthem, we understand and respect it being a personal decision."
Marshall's action comes a day after Seahawks wide receiver Doug Baldwin and defensive end Cliff Avril told reporters they were considering not standing during the national anthem before Sunday's game against the Dolphins. Baldwin tweeted Thursday that the team will take part in a pregame demonstration Sunday.
"To express a desire to bring people together, our team will honor the country and flag in a pregame demonstration of unity," Baldwin posted.