'Spot the ball' was a staple of local newspaper competitions - an action shot of a game with the ball removed by presumably pre-digital photographic trickery. Entrants were invited to mark a cross where they thought the ball might have been, and the closest to the original centre co-ordinates won a prize.

So yeah, surprisingly tricky, but you could set up a big training set along similar lines.

It would be difficult from player 'positions' in a single image, but the example given is obviously wrong if you consider motion of player positions over time--those player positions going back and forth with the 'ball' moving by itself along the sidelines.