A method is provided for safely delivering actuators such as balls from a ball injector to a downhole tool in a wellbore. A structure or carrier medium, such as a slug of gel or foam, is introduced to a bore of injector and the ball is injected into the bore for support by the carrier medium. A displacement fluid, such as fracturing fluid, is pumped into the wellbore to drive the carrier medium and ball. Each slug and ball can be retrieved at a ball catcher at the wellhead.