Two of our rescue dogs took a long time to learn to play - and then it was only sort of. The first is a hound mix who was raised on a rope tied outside with no shelter etc. My ex went up to the house, knocked on the door and asked if she could have him - they said yes. He had rope burns around his neck, infected ears from fly bites, no muscle tone (he was a little more than a yr old and was kind of floppy like a puppy because he had been on the 6 ft rope so lone) - he was scared of everything at first - stairs, toys, the food bowl (we had to teach him to eat out of bowl - at first we still had to pour it on the floor for him). He was actually scared of the stuffed toys at first - we had another dog who played with them and I think she showed him how to kind of play with them. He never really learned to play with us and toys, but he did come to love stuffed toys that he could just carry around and sleep on (sometimes he would make a mound and get in the middle of them). He would play tug with the other dog - but never with us - he would just slink away so we stopped torturing him by trying to do it with him. He is a cuddledog (he is 12 now)- but never got to be a really carefree playful one.