I'm not really sure, but he could have started by just having the dog hold the bat in his mouth and thrown the ball slowly so that it would hit the bat. After anywhere from a couple of times to many times of repeating that, he could have walked further away, threw the ball a little faster and just worked from there.

You saw the dog actually swinging that bat before he threw the ball wanting him to throw it. I have no idea how long it might have taken to train him but that is a class act dog to say the least!

Kudos to the owner!

FWIW

Yes, they are both predictable, Haha.

He taught in steps.  The dog may have known how to hold the stick and naturally hit the ball when it was thrown.

That’s how I think he did it. I think the dog naturally held the stick and would shake its head. Then the owner worked from there.

Sounds likely. Then just replace the stick with a plastic bat. I've seen numerous dogs carry all kinds of sticks, branches, etc. home and so to work from there would probably be easier. But getting him to swing to throw the ball I thought was the cutest... he seems to really like it.

FWIW

He had fun.

I think they both were having fun! (* CHUCKLE *)

FWIW

They were.