Abstract: An eddy current probe, especially useful for inspecting roll plugs in steam generator tubes, has a detector assembly which is automatically extended and retracted in a radial recess in an elongated body to prevent damage to the detector assembly during insertion and retraction of the probe, yet permits the detector assembly to bear against the interior wall of the roll plug, including the roll zone. In one embodiment, a mechanical actuator in the form of a pair of finger members spring biased radially outward operate through camming surfaces to rotate a pivot member which retracts the detector assembly; however, when the probe enters the bore of a roll plug the fingers are compressed to permit extension of the detector assembly. In another embodiment, a linear actuator such as a solenoid rotates the pivot member to extend and retract the detector assembly.