An S1 radiculopathy is usually due to a HNP getting the S1 nerve root as it passes over the L5/S1 disc on its way to exit the spinal canal at the S2/S1 foramen. The calf muscle is very big and strong and it’s unusual to find much of any weakness in it, so more often the signs are decreased pin prick sensation over the little toe and/or a decreased or absent ankle jerk reflex.
Any sign or an S1 radiculopathy increases the likelihood of a lumbar HNP to about 70%. So this would indicate that a CT or MRI scan would help in treatment planning. Of course non-operative treatment should be vigorously pursued, but if that fails or has failed and the scan shows a HNP, then surgery would be a consideration.