-- Free-agent quarterback Colin Kaepernick is filing a grievance under the latest collective bargaining agreement against NFL owners for collusion, according to a court filing obtained by ABC News.
Kaepernick is not going through the NFL Players Association but has instead hired attorney Mark Geragos, who has represented several high-profile clients, including Michael Jackson, former NASCAR driver Jeremy Mayfield and musician Chris Brown.
The filing was first reported by Bleacher Report.
Kaepernick drew national attention last season when he knelt during the national anthem before games to protest social injustice. His kneeling led to a movement that has spread through the league while also being vilified -- including multiple negative comments from President Donald Trump.
He has not been with an NFL team since severing his contract with the San Francisco 49ers in March. Sources told ESPN's Adam Schefter at the time that Kaepernick would stand during the anthem in 2017.
Most recently, the Tennessee Titans were in the market for a backup quarterback given? Marcus Mariota's hamstring injury,?and coach Mike Mularkey said "I'm not aware if there was" interest in Kaepernick.
Mularkey said familiarity was the biggest factor in the team's decision to sign Brandon Weeden.?
In September, Ray Lewis said the Baltimore Ravens chose not to sign Kaepernick after his girlfriend posted a "racist" tweet featuring the former All-Pro linebacker and owner Steve Bisciotti. Coach John Harbaugh did not directly address the assertion.
Earlier this month, Kaepernick spoke with CBS Sports' Jason La Canfora for an off-camera interview and reportedly said he'd go anywhere to work out for an NFL team and was fine if that workout was kept private. Kaepernick said he was looking for an opportunity to play and just wanted to be judged as a football player.?
Kaepernick said he has remained quiet about his desire to play, to avoid causing a distraction. His agent has reportedly been reaching out to all 32 teams to note his availability.
The NFL has not reached out to Kaepernick to discuss social issues. Trump's comments last month drew a leaguewide response as more players chose to kneel, link arms or otherwise react during the national anthem.
The Associated Press contributed to this report.