Well, maybe to catch a ride to the park.
Usually at this park I'll bat the ball across the field, he'll chase it down and bring it back to do it again, and again, and again, etc.. Lately he's been taking the ball and playing by himself on a little hill by the creek, looks like it's more fun, especially when it occasionally goes into the water.
https://www.youtube.com/watch?v=tJP9UH3sgOc