An assembly for a valvetrain having a valve, a lash adjuster, and a lobe. The assembly includes a shaft, a bearing supported by the shaft for engaging the lobe, and a rocker having a pad for the valve and a socket for the lash adjuster. Walls are disposed between the pad and socket, have inner and outer wall surfaces, and define a valley for the shaft. Upwardly-opening arc-shaped bearing surfaces are disposed longitudinally between the pad and socket spaced laterally from each other and support the shaft when the bearing engages the lobe. A retention element formed in each wall with a depressed portion spaced from the outer wall surface and a lip portion arranged under the depressed portion extends into the valley above the bearing surfaces such that the shaft is prevented from moving out of the valley in absence of engagement between the bearing and the lobe.