He might not be interested in anything that doesn't move fast or squeak,.
My greyhoundxcollie only wants to play with things that squeak and or look like and animal/bird.
@ as 'walking lady' mentioned, i have never had a dog in my house that doesn't want to play with the stuffed duck, goose, pheasants we have, they all make different noises similar to the animal, and you can get them cheap online most pet shops.