When I first heard Colin Kaepernick was filing a collusion grievance against NFL owners because none of them have signed him this year, I figured his case seemed pretty weak on the surface but I wondered if maybe his camp had something they considered evidence that might give them a reason to think they could win. Phone transcripts, perhaps, of the Raiders calling the Steelers and the Chiefs calling the Eagles, where all of them agree not to touch Kap because he needs to be punished for his anti-American apostasy.
That seems highly implausible, but if it did exist and you had it, I guess I can see why you might give the grievance a shot.