In the time since Colin Kaepernick first took a knee during the national anthem in protest of police brutality and violence against people of color, other teams and players have voiced their support of Kaepernick and taken up their own demonstrations. But the limit to that support is evident when it comes to actually giving Kaepernick a contract with a team. According to a report from the Washington Post, Kaepernick has now filed an official grievance against the NFL, accusing team owners of colluding to keep him from playing.

The SF Examiner says that Kaepernick has turned to criminal defense attorney Mark Geragos, who issued a statement explaining the grievance. He wrote:

If the NFL (as well as all professional sports leagues) is to remain a meritocracy, then principled and peaceful political protest — 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 … Protecting all athletes from such collusive conduct is what compelled Mr. Kaepernick to file his grievance.

At the end of last season, Kaepernick opted out of a contract with the 49ers, who went on to say that they were planning to release him anyway. Since then, Kaepernick has been a free agent in search of a new team, and as any football fan can tell you, that search has not been a fruitful one.

WaPo brings up one example in the Tennessee Titans, who signed on Brandon Weeden to add depth to their quarterback position behind Matt Cassel. As USA Today pointed out in a story about the fan response to Weeden's signing, there were more than enough NFL enthusiasts who decrying the move on Twitter. There were even quite a few fans upholding the idea that Kaepernick has essentially been blackballed from playing in the NFL. CBS Sports pointed out that even Weeden chimed in with an opinion on Kaepernick's ability to play, telling the Tennesseean: "He's had a heck of a career. He played in a Super Bowl. Obviously, he's done a lot of really good things. I think us as players, we all kind of firmly believe that he's a good enough player to play in this league."

But if Kaepernick and Garagos are trying to prove collusion, they may have an uphill battle ahead of them. In order to prove collusion in court, there has to be hard, verifiable evidence that at least two people engaged in a conspiracy against a person. WaPo spoke with Gabriel Feldman, director of Tulane University's sports law program, who told them: "Disagreement over personnel decisions, as obvious as it may seem to someone looking at this, does not provide evidence of collusion. There has to be some evidence of an explicit or implied agreement. There has to be proof of a conspiracy."

Related: Sports Reporter Retracts Incorrect Report Saying Kaepernick Would Stand For National Anthem Again