Kaepernick Wears Muhammad Ali Shirt as He's Blasted for Again Kneeling for National Anthem

The athlete wore the shirt to and from Sunday's game.

San Francisco 49ers quarterback Colin Kaepernick was once again defiant as he spoke to reporters while wearing a T-shirt with Muhammad Ali’s image on it Sunday afternoon.

Read: The Champ's Final Round: Muhammad Ali Is Laid to Rest

The star arrived to New Era Field in Buffalo, New York, while wearing the shirt under a black blazer. Following the game, he donned the outfit again during a post-game press conference.

The shirt is symbolic due to the late boxing icon’s political stance against the Vietnam draft of the 1960s and the criticism he took, which resulted in a 5-year ban from the sport and revocation of his boxing license.

The 49ers star faced a torrent of jeers from Buffalo Bills fans as he walked onto the field Sunday and the boos continued as he took a knee during the national anthem.

A group of Bills fans marched to the stadium in solidarity with Kaepernick and got down on one knee during the national anthem.

According to reports, some fans were selling shirts with the quarterback’s image that read “Shut Up and Stand Up” and an image of Kaepernick in crosshairs that read, “WANTED Notorious Disgrace to America.”

Read: Friend of Muhammad Ali Recalls Boxing Legend's Generosity: 'Whenever He Got Money, He Gave It Away'

When Kaepernick’s anthem controversy began, filmmaker Spike Lee compared the athlete to Muhammad Ali.

Lee told The Wrap in August: “How can you love Muhammad Ali and not love [Kaepernick] for the stance he took?”

Watch: As Kaepernick Takes a Knee, More Athletes Refuse to Stand During National Anthem