a door system having , a door , a plurality of track sections having a cross - section defining an interior track area that is accessible though an opening therein , a roller received in the interior track area and coupled to a shaft that is operatively interconnected with the door , and a guard carried by the shaft and at least partially enclosing the roller , wherein the guard includes a shield wall that is positioned within the interior track area and at least partially obstructs the opening in the area of the roller .