A large crowd gathered Wednesday at the NFL’s Park Ave. headquarters in midtown Manhattan as part of a planned rally to protest the league’s failure to sign Colin Kaepernick. Before the event, the NAACP announced that it was requesting a meeting with NFL Commissioner Roger Goodell and other league executives to discuss the quarterback “being victimized and discriminated against because of his exercise of free speech.”

In a letter to Goodell, the NAACP said “many in our community” are viewing Kaepernick’s ongoing inability to latch on with a team as “a league-wide set of retaliatory actions” against him. The former 49er is widely believed to be getting blackballed by the NFL because he protested racial injustice last season be kneeling during the national anthem, inspiring other athletes along the way to emulate his example.

“In order to determine the best approach to protecting players from being unfairly persecuted for their political beliefs,” the civil rights group said in its letter, “we hope to begin a dialogue with you and any other members of NFL leadership who have a vested interest in preserving the league’s integrity.” At Wednesday’s rally, the NAACP handed out T-shirts showing an image of Kaepernick kneeling, with a fist emerging from his hair.

The rally, called United We Stand, was attended by what ESPN’s Josina Anderson estimated was approximately 1,000 people, and the was a heavy police presence on hand, as well. Organizers, including CNN contributor Symone Sanders, sent their own letter to Goodell, in which they said (via BuzzFeed), “We will not be silent as the NFL actively participates in the ostracization of Mr. Kaepernick.”

Organizers called on the NFL to “implement a policy guaranteeing the freedom of speech of players to express their concerns on social justice issues,” including tampering penalties for teams “suspected of prohibiting or outright denying a player his rights.” They also requested that the NFL “establish a unit tasked with developing a league wide plan to improve racial equality.”

Activists held up signs with messages such as “NFL blackout” and “Kaepernick we kneel with you,” as several speakers vowed to boycott the league until the quarterback was signed. One attendee’s sign highlighted the letters “N-F-L” in “Negro fall in line!!!”

Olympic fencer Ibtihaj Muhammad, who last year became the first American woman to wear a hijab while competing for the United States in the Games, was among those at the rally. She reportedly said she would “definitely” kneel in protest, while others invoked the raised fists of sprinters Tommie Smith and John Carlos on the medal podium at the 1968 Olympics.

Goodell has denied in the past that Kaepernick is being deliberately shunned by NFL teams, defending his league as a “meritocracy.” The commissioner said in June that “if a football team feels that Colin Kaepernick, or any other player, is going to improve that team, they’re going to do it.”

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