My foster dog never knew how to play either. And he was a bit inhibited as far as tugging with me until he built trust. A ball would bounce off his head before he figured out timing to catch it. Within a few weeks he was chasing frisbees and catching them with grace. He tugged with me too.
Flirtpoles are good as they aren't as intimidating as a person possibly bending over the dog or getting in the dogs space.