The NFL has filed a grievance against the NFL Players Association, alleging that union leaders, including President JC Tretter, have advised running backs to “consider feigning or exaggerating injuries” to help increase their leverage in contract negotiations. The grievance will be reviewed by an arbitrator.

In a memo sent to the league’s management council executive committee and obtained by The AP, the NFL said the union made the suggestion to during a Zoom meeting before the season.

Those who took the union’s advice and faked an injury would be violating the collective bargaining agreement, the league argued.