Here is a CP from Bretman's answer to the question from page 4:
The batter is out for interference if her discarded bat hits her batted ball (ie: bat hits ball).
If the bat is not moving and the ball hits it (ie: ball hits bat), that is not a violation- with one possible exception!
The umpire could judge that the batter discrded her bat to purposely put it in the path of the ball. In that case, it is possible for the bat to be lying still, have the ball roll into it and still have interference.
So, the "ball hits bat/bat hit ball" axiom works most of the time, but not all of the time, because of that one rare exception.
Other freaky stuff to consider for batted balls and discarded bats colliding:
- If the bat and ball make contact over foul ground, and it is not ruled interference, the ball is immediately dead and it is a foul ball. A bat lying in foul ground is treated as "an object not natural to the field", like a fence or wall.
- If the bat and ball make contact over fair ground, and it is not ruled interference, the ball is not automatically fair. A bat lying on fair ground is treated as "a natural part of the field", like a pebble or dirt clod. The "fair/foul" determination is made depending on where the ball is first touched by a player, eventually rolls to or settles.
- If the bat hits the ball over foul ground, and the umpire judges that the ball had a chance to become fair (like on a ball rolling along the foul line or heading toward fair ground), he can rule interference just like if the bat hit the ball over fair ground.
- The bat/ball contact must be made with a "whole" bat for all these rules to apply. If a bat is broken, the broken bat is considered as "a natural part of the playing field" and interference cannot be called.