Presently disclosed reamer devices include a longitudinally-extending slot formed through a cutter head portion and a portion of a shaft, thereby allowing engagement of the reamer device with a guide pin inserted into a patient's glenoid by passing the guide pin through the slot and into an interior cannula track extending longitudinally through the interior of the shaft and cutter head portion. Presently disclosed reamer devices may be configured to engage the guide pin when the cutter head portion is positioned at a location medial to the patient's humeral head. Presently disclosed systems include such reamer devices and a guide pin, such as a dual diameter guide pin having an enlarged portion and a smaller portion. Dual diameter guide pins may interact with the interior cannula track of the shaft of the reamer device to serve as a depth limit for advancement of the reamer device along the guide pin.