Colin Kaepernick has filed a grievance against the NFL, accusing the 32 owners of collusion.

Former San Francisco quarterback Kaepernick has remained unemployed through the first six weeks of the NFL season after leaving the 49ers in the offseason, even when injuries to other starting quarterbacks left teams in need of help at the position.

"We can confirm that this morning we filed a grievance under the CBA on behalf of Colin Kaepernick," his attorney Mark Geragos said in a statement. "This was done only after pursuing every possible avenue with all NFL teams and their executives.

"If the NFL (as well as all professional sports leagues) is to remain a meritocracy, then principled and peaceful political protests -- which the owners themselves made great theater imitating weeks ago -- should not be punished and athletes should not be denied employment based on partisan political provocation by the Executive Branch of our government.

"Such a precedent threatens all patriotic Americans and harkens back to our darkest days as a nation. Protecting all athletes from such collusive conduct is what compelled Mr. Kaepernick to file his grievance. Colin Kaepernick's goal has always been, and remains, to simply be treated fairly by the league he performed at the highest level for and to return to the football playing field."

The 29-year-old says his agent reached out to all 32 teams to make sure they were aware of his interest in playing this season.

Kaepernick has been a controversial figure since he first sat and then knelt during the national anthem before games with the 49ers in the 2016 season. The move was the beginning of what turned into league-wide protests earlier this season after U.S. president Donald Trump made critical comments of players who don't stand for the national anthem.

Kaepernick has become one of the highest profile figures in the sport following his kneeling protests (Getty / Thearon W. Henderson)

Kaepernick and his legal team are claiming the owners violated terms of the collective bargaining agreement, specifically a clause that prohibits teams from acting together in regards to a player's employments status.

"No club, its employees or agents shall enter into any agreement, express or implied, with the NFL or any other club, its employees or agents to restrict or limit individual club decision-making," the CBA states, adding that the clause applies to "whether to negotiate or not to negotiate with any player" and "whether to offer or not to offer a Player Contract to any player."

NFL commissioner Roger Goodell has stated on multiple occasions this season that Kaepernick is not being blackballed.