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Nike ad features Colin Kaepernick
00:36 - Source: CNN
CNN  — 

Former San Francisco 49ers quarterback Colin Kaepernick has been out of work for more than 800 days. But he says he’s never stopped being ready to play football.

The athlete-turned-activist posted a 59-second video on his Twitter account Wednesday of him working out to show that he’s ready to play again.

Kaepernick has not played in the National Football League since the 2016 season when he sparked controversy by sitting, then kneeling, during the National Anthem before several 2016 NFL preseason and regular-season games to protest the police shootings of black men and other social injustices faced by African-Americans.

Kaepernick became a free agent in 2017. No team offered him a contract, and that October, he filed a grievance against the league, accusing team owners of colluding to keep him from being signed. He and former teammate Eric Reid, who knelt with Kaepernick, settled their collusion grievances cases against the NFL in February.

A number of quarterbacks have been signed to NFL teams, but Kaepernick remains unsigned. Preseason begins Thursday night for most NFL teams.

In the video, the words: “Denied work for 889 days,” flashes across the screen.

“5 a.m., five days a week, for three years. Still ready,” says Kaepernick, who played for the 49ers for six years.

Attempts by CNN to contact representatives for Kaepernick and the National Football League Players Association were unsuccessful.

CNN’s Jill Martin and David Close contributed to this report.