[jmkupka]

I recall a not-so-recent thread describing a similar situation to mine:

A popup lands beyond the pitcher's plate between F1 & F4, and backspins untouched til it rolls across the baseline this side of 1B.

The discussion dealt with the triangulation of 1B, 3B & Home plate.

In my case, I called it foul, and got no argument. I forget what the verdict was in the thread.