It's most definitely a fake. How they did it ?? I have no frickin' clue.
However, every time the ball comes back into towards the batter... just as the batter takes the same steps backwards and frontwards.... you can see the guy off to the right move exactly like he did during the last round of bouncing balls, but the big giveaway is.... the trees in the distance suddenly change their wind direction and it's identical each time. They are blowing in the breeze, suddenly stop and start over.