A medical clinic in Illinois is accusing the NFL of instructing its insurance carrier to deny claims made by former players under the auspices of the league’s disability plan. The allegations are outlined in a lawsuit that also accuses the league of retaliating against the clinic for providing independent diagnostic services in lieu of the concussion settlement. Advanced Physicians S.C. first filed the suit in Illinois state court in March, but the case was moved to federal court on Thursday. According to the suit, which was first reported by Law360, “[t]he NFL doesn’t want to pay its former players disability payments under the disability plan” that had been collectively bargained between the league and the NFLPA. According to the suit, Advanced estimates it has treated more t…