An insertion mechanism for a drug delivery device including a trocar, a housing, and a manifold in fluid communication with a fluid pathway connector and movable relative to the housing between a first manifold position adjacent to a proximal end of the housing and a second manifold position adjacent to a distal end of the housing. A hub carrying the trocar or hollow delivery needle is removably connected to the manifold, the hub being movable relative to the housing between a first hub position adjacent to the proximal end of the housing and a second hub position adjacent to the distal end of the housing. A power source is configured to generate rotational motion. A motion conversion mechanism operatively connects the power source and the hub, and is configured to convert the rotational motion into linear motion of the hub.