A tappet assembly for use in translating force between a camshaft lobe and a fuel pump assembly via reciprocal movement within a tappet cylinder having a guide slot. The tappet assembly includes a bearing assembly having a shaft and a bearing rotatably supported by the shaft for engaging the lobe. An intermediate element has a shelf for engaging the fuel pump assembly, and a pair of arc-shaped bearing surfaces rotatably engaging the shaft when the bearing engages the lobe and the shelf engages the fuel pump assembly. The intermediate element includes a pair of lock apertures. The bearing assembly further includes a pair of shields supported on the shaft of the bearing assembly with the bearing interposed between the shields. The shields include a pair of opposing fingers for engaging the lock apertures so as to substantially retain the bearing assembly to the intermediate element and so as to substantially retain the shaft of the bearing assembly within the annular body in absence of engagement between the bearing and the camshaft lobe.