The NFL players union has filed a grievance against the league over changes to its personal conduct policy. League officials said Friday they want players and others in the NFL to be held to stricter standards. The NFL said in a statement: ''Clearly, the union does not share that belief.'' Officials for the NFL Players Association did not immediately respond to requests for comment. The union and the league have been at odds over the personal conduct policy since both groups began navigating the Ray Rice domestic violence case. More...