A common rail fuel pump includes a cam shaft with at least one cam rotatably supported in a pump housing. A plurality of tappet assemblies are each reciprocatingly movable in the pump housing, and include an axle pin mounted in a tappet, and a roller mounted in contact for rotation about the axle pin. Each end of the roller includes a plurality of non-contiguous planar thrust surfaces separated by lubrication grooves. A lubrication pathway for the roller includes in sequence a lubrication passage that opens to a roller bearing surface, movement along the roller bearing surface into the lubrication grooves, and then between the planar thrust surface of the roller and a counterpart thrust face of the tappet responsive to rotation of the roller on the cam shaft.