I think you really have to look at 2 ways in which the batter can interfere with the catcher "fielding the ball." One is the fielding of the pitch itself before an opportunity to field it has occurred, and the other is when the opportunity to catch the pitch has occurred, the pitch is not caught, and the BR then interferes with the catcher's attempt to retrieve it.
Interference before the opportunity to field the pitch could result from a batter's backswing hitting the catcher. Evans states:
Contrary to rule 6.06(c) Notes, the batter is declared out for interfering on his backswing on a strike three pitch when the batter contacts the catcher or the ball before it is securely held. The ball is dead and no runner may advance.
The other potential arises when the pitch is not caught and is loose as a result of the catcher's inability to glove the pitch. While Fed rule and J/R's interpretation for OBR indicate any such interference after a dropped 3rd strike is loose must be intentional (and unintentional interference is nothing), Evans states differently in the JEA where he provides us these plays:
- Situations: One out...runner on 2nd. The batter swings and misses "Strike 3" in the dirt. The catcher blocks the ball and deflects it in front of the plate. In leaving the batter's box, the batter kicks the ball several feet into foul territory. The runner on 2nd advances to 3rd and the BR is safe at 1st. What's the call?
RULING: The batter is out for hindering the catcher's attempt to field the ball. The ball is dead and the runner returns to 2nd. Though the kick was unintentional, it prevented the catcher from making the play at 1st base. Contact with the ball is not the deciding factor. If the catcher has a legitimate chance to make a play after contact, no interference should be ruled. [my emphasis]
- One out...runner on 2nd. The batter swings and misses "Strike 3" in the dirt. The batter takes off for 1st and the catcher deflects the ball into him as he is en route to 1st. The runner from 2nd advances to 3rd but the BR is thrown out at 1st. What's the call?
RULING: This ball is alive and in play provided the umpire rules that the batter's actions were not a hindrance to the catcher making a play. This is umpire's judgment.
Note: When a batter-runner has left the batter's box and is hit from behind by a ball deflected by the catcher, he shall not be called out for interference.
It appears Evans looks not at the mere contact with the ball, but if the severity of the contact (in the umpire's judgment) causes the catcher to lose his opportunity to make a play.
While the ruling of no interference is in concrete for Fed, conflict exists between the authorities for OBR. I'm apt to rule in OBR that it's not interference if contact with the ball occurs immediately upon the batter leaving the box before he has had opportunity to see the ball. But after the batter has had opportunity to see the ball, I'd rule that any contact thereafter would be intentional----unless the ball was to contact the fielder from behind him. IMO, after the batter has had opportunity to see and react to the ball, he should be attempting (and required) to avoid it.
Just my opinion,
Freix