Tennessee Titans receiver Rishard Matthews has no plans to stand for the national anthem anytime soon.
Matthews said he was extremely upset over United States president Donald Trump's "son of a b****" comment on Friday when he said NFL players who kneel during the anthem should be "fired".
"I plan to kneel until the president apologises for the comments that he made, because I felt like those were very disrespectful comments that he made," Matthews said on ESPN on Tuesday.
"The league is made up of I think ... over 70 per cent African Americans, so the people that would be kneeling for this cause would be African Americans.
"To keep it honest, he was calling a lot of us, and I feel that he was calling myself, a S.O.B., and that's not OK and very disrespectful. So I plan to kneel until the president apologises."
NFL commissioner Roger Goodell denounced Trump's comments over national anthem protests while several NFL owners followed, calling the president's remarks and tweets "divisive" and "counterproductive", with some standing in solidarity with their players prior to Sunday's games.
Matthews grew up in a military family and his brother died in Afghanistan. He has been outspoken against police brutality and racial inequality, but his military ties made him hesitate about protesting during the national anthem.
However, Matthews said his platform and the fact he is a minority, along with Trumps tweets, made him realise he could have an important role in protesting racial inequality.
He said if the Titans did not remain in the locker room during Sunday's game against the Seattle Seahawks, he would have knelt on the sideline.
"I'm tired of hearing 'stick to sports.' It comes down to right and wrong in this world," Matthews said Sunday.
"If you see wrong and don't say anything that's wrong. As minorities, what do you want to happen before we say anything? They tried to have a silent protest and look what happened. It's your right to stand or sit down. You have that right, that freedom of speech, and you're not allowing that to happen."