For the first time this season,India Archives Colin Kaepernick started for the San Francisco 49ers -- and some Buffalo Bills fans made sure he didn't feel welcome.

As Kaepernick kneeled Sunday during the national anthem, Bills fans booed and chanted "USA! USA!"

SEE ALSO: President Obama's take on the Colin Kaepernick anthem controversy

Outside the stadium, people sold T-shirts trashing the San Francisco quarterback, including one with Kaepernick in a rifle scope, according to Sports Illustratedwriter Robert Klemko.

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Klemko also captured this tailgating incident:

There was other anti-Kaepernick merchandise at the game as well.

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But not everyone was rooting against the San Francisco quarterback.

Kaepernick started kneeling during the national anthem in the NFL preseason as a protest against police brutality and racial injustice. Since then, other athletes in the NFL and outside the league have joined him.

Last week, San Francisco announced that Kaepernick would take over for Blaine Gabbert as the 49ers starting quarterback.

On Sunday, Kaepernick walked into New Era Field (formerly Ralph Wilson Stadium) in Buffalo, New York, sporting a Muhammad Ali shirt. Ali was one of the most politically outspoken athletes in history, receiving a three-year boxing ban after he refused in 1967 to fight in Vietnam.

Despite the controversy, the 49ers are hoping Kaepernick can give the team a boost after its dismal 1-4 start to the 2016 season.