Forget the ball for a while and try a rolled up sock that you have worn, and only do a couple of retrieves a day.
Let the pup run around with the sock in his mouth the idea is to get him to be used to carrying the retrieve item, lay on the floor he will eventually bring it to you or do this in a hallway so he has to bring it to you. but crouch down low don't be in any rush to take the retrieve from the pups mouth.
The sit before the throw and straight back to you with perfect delivery can all come later, at this age it just has to be fun fun fun .
Once he picks up the sock no problem cut the toe off the sock and use it to cover the ball, then cut a bit more sock off then a bit more until there is just a thin band of sock around the ball eventually you will be back to just the ball.
Forget the treats for now you want the retrieve to be the treat.
