Is this on the pad on the bottom of the foot by the toes, or higher up on the leg(it's hard to tell from the photos, but it looks higher up on the leg)?
Then it's going to be something else not related to hopping around on the floor. So it's going to be something in the environment that the leg is getting rubbed on a regular basis, a freak occurrence of the fur getting stuck on something and yanked out, or your rabbit is self mutilating the area possibly because of internal pain and/or discomfort in the leg or skin on the leg, and this would likely require a knowledgeable rabbit vet looking into and a possible skin biopsy or xrays of the leg done. These are the possibilities I would be looking at.