The NFL announced Monday that it is filing a grievance against the NFLPA, claiming that the union advised players to feign injury to gain leverage in contract negotiations.

The league announced the grievance in a memo that was reported by NFL Network's Tom Pelissero. The memo names NFLPA president and former Cleveland Browns center JC Tretter.

Running back negotiations became contentious this offseason as All-Pros Saquon Barkley, Josh Jacobs and Jonathan Taylor failed to secure long-term contracts. Barkley and Jacobs eventually signed one-year deals after being placed on the franchise tag while Taylor remains sidelined on the physically unable to perform (PUP) list on the final year of his rookie contract.