Transcript for Colin Kaepernick files grievance against NFL
We move on to Colin Kaepernick who is taking action against the NFL claiming team owners colluded to keep him from playing because he led the movement to kneel during the national anthem as a protest against police violence. Ryan Smith has the latest. Reporter: You know, Colin Kaepernick has yet to speak out publicly about his lack of NFL employment but now he's letting his lawyers do the talking CLA claimicla claiming owners are making an example out of him. This morning former San Francisco 49ers quarterback Colin Kaepernick challenging the NFL accusing the league and all 32 team owners of colluding to keep him off the field. According to dock thes obtained by ABC news, the unsigned free agent quarterback claims multiple NFL head coaches and general managers stated they wanted to sign Mr. Kaepernick only to mysteriously go silent with no explanation and no contract offer made. Kaepernick pointing to his refusal to stand during the national anthem last season as a way to protest racial injustice as the reason for his unemployment. A response he said at the time he anticipated. You're going to have that backlash for trying to fight for people. Reporter: With more than three dozen quarterbacks signed since Kaepernick hit free agency his lawyers now filing a grievance with the NFL for violating the league's collective bargaining agreement pointing out Kaepernick is an ideal candidate with six seasons on the 49ers where he led his team to the super bowl. When you file a grievance through the collective bargaining process you're going to have your grievance aju adjudicated by an arbitrator and they'll have to defend their decisions not to hire Kaepernick, it's going to come down to what evidence is produced during the discovery process. Reporter: Now the NFL has yet to comment but Roger Goodell previously dismissed claims of Kaepernick being blackballed saying that hiring decisions are left up to individual teams. It's not going to be easy for Kaepernick to prove collusion. No, it's really tough. You talk about he's got to prove either two teams or a few teams or a team in the NFL got together and tried to keep him from employment and he's got to prove that by clear and convincing evidence so he got to produce something actual, e-mails, something in writing at this point and that's very difficult to do, I think. Ryan, thanks very much.
This transcript has been automatically generated and may not be 100% accurate.