For a week or so now, he will get up from sleeping and hop around and not put his right back leg on the ground. When we rub it for a few seconds, he starts walking totally normal. Can't figure out if it's going to sleep or what. He doesn't yelp or seem to be in pain, just holds it in the air and hops on three legs. Any ideas? If it keeps up we will probably have to take him to the vet, but he hates it there and I don't like to traumatize him.