Eric Reid did not let NFL teams get away with posting black squares on Twitter Tuesday in purported solidarity with the fight for racial justice while quarterback and activist Colin Kaepernick remains unsigned in the league.

Reid, an NFL free agent and former safety for the Carolina Panthers, responded to a number of football teams’ tweets about the Black Lives Matter movement by reminding them that Kaepernick led a wave of peaceful protests against racial injustice and police brutality in 2016 when he began kneeling during the national anthem at NFL games.

When the Houston Texans tweeted a black square on Tuesday with the caption, “Listening,” Reid replied: “Blackballing.”

The San Francisco 49ers tweeted a black square captioned “Black Lives Matter” with the hashtag #BlackoutTuesday.

People began posting black squares on social media platforms on Tuesday as part of a “Blackout Tuesday” campaign in response to the police killing of George Floyd.