The invention concerns a mechanical system (1), forming a cam follower or a rocker arm, and comprising: - a support element (10), - a pin (30) extending between two opposite ends along a first axis (X1) and supported by the support element (10), and - a roller (40) movable in rotation relative to the pin (30) around the first axis (X1) and adapted to roll on a cam, wherein the support element (10) comprises at least a first part (20) and a second separate part (11) which, when fitted together, together delimit a lubricating groove on an external surface of the support element (10).