San Francisco 49ers quarterback Colin Kaepernick knelt with his arms folded during the performance of the US national anthem during a pre-season game in San Diego.
The move continues his protest against what he sees as racial injustice and police brutality.
Kaepernick, 28, has pledged to continue sitting during performances of The Star Spangled Banner before NFL games, a move that has been both criticised and cheered by commentators.
He was met by heavy boos from the crowd during pre-game warm-ups at Qualcomm Stadium in San Diego, which is home to US Navy and Marine bases.
49ers safety Eric Reid, who did not take part in the final pre-season game, took a knee next to Kapernick during the anthem.
Post-game, Reid stated that it was Kapernick's idea to take a knee and not sit, because it showed more respect to the anthem and military.
The game also coincided with "Salute the Military night," which saw 240 sailors, Marines and soldiers present a US flag and a pre-game parachute jump by retired Navy SEALS.
Kaepernick, who led San Francisco to the 2013 Super Bowl but has since been demoted to backup, has said he would not show pride in the flag of a country that oppresses people of colour, citing police brutality.
Reuters/Newshub
