An introducer assembly that may be employed to implant a medical device includes an introducer shaft, and an anchor sleeve and a deployment tool mounted on the shaft. According to some methods, the sleeve is deployed onto an elongate body of the medical device, after the body has been advanced through a lumen of the introducer shaft and to an implant site within a body of a patient, by pulling the introducer shaft proximally, out from the body of the patient, while holding the deployment tool in place, relative to the advanced body of the device.