Stray Ball Enter Field of Play

[tibear]

Strange situation which I think has no obvious answer.

Have a couple of diamonds that are back-to-back and every once in while a foul ball ends up going into the other field.

I think it is obvious that if there isn't a play going on at the time that you immediately call time and get the "stray" ball off the field.

The question comes in where the foul ball is noticed while an active play is happening, either a play on a runner, hit ball or even a pitch is in the air.

How would you deal with the situation? Let the play continue as long as the stray ball doesn't have a direct impact on the play? Kill the play immediately and place runners as if it was spectator interference? On a pitched ball, immediately call "no pitch" and kill the play?