The image surfaced on social media by a fan who tweeted: “One of the Niners cheerleaders is taking a knee”.
Taking the knee has since become a symbol of protest to raise awareness against racism and police brutality.
The movement began in 2016 by former 49ers quarterback Colin Kaepernick.
At the time he said: “I am not going to stand up to show pride in a flag for a country that oppresses black people and people of colour.”
Mr Kaepernick was credited for raising awareness for oppression in America and inspired football players across the states to also ‘take a knee’.
Mr Kaepernick opted out of his contract with the San Francisco 49ers in March 2017 and is now suing the National Football League, he has alleged that NFL owners have colluded against him.
No longer employed by a football team, Kaepernick is now a brand ambassador for sports giant Nike.
US President Donald Trump has been a heavy critic of the movement and warned players should be “fired” if they disrespect the US flag.
He wrote: “If a player wants the privilege of making millions of dollars in the NFL,or other leagues, he or she should not be allowed to disrespect our Great American Flag (or Country) and should stand for the National Anthem.”
Another tweet said: “If not, YOU’RE FIRED. Find something else to do!”
Since the widespread protests the NFL has issued new guidelines prohibiting kneeling during the anthem, but allows them to stay in the locker room.
In an interview with Fox & Friends the President responded to the new guidelines with a stark warning to players.
He said: “I don’t think people should be staying in the locker rooms, but still I think it’s good. You have to stand proudly for the national anthem. Or you shouldn’t be playing, you shouldn’t be there. Maybe you shouldn’t be in the country.
“You have to stand proudly for the national anthem and the NFL owners did the right thing if that’s what they’ve done.”