Fielder's balk?

[JJ]

MANY years ago when I went to Wendlestedt's school I only missed one quiz question - the very first of the 180 or so total that were asked during the five weeks.
"The leadoff batter hits the first pitch over the left field wall for a home run. Then the umpires notice there was no left fielder on the field when the ball was hit. What's the outcome?"
My logic of course was "screw the team that screwed up" - penalize the DEFENSE since they screwed up. WRONG!
"Nullify the pitch. Put the fielder out there. Resume the game."
Yes, this is only somewhat related to the OP here, but it's an amusing story.
I'll go with Bob here - if I don't see it during the pitch, I won't see it after the pitch. One foot in fair territory will suffice.

JJ