Found this gem on Google flights:
https://www.google.ca/flights/#searc...-PHLPIT1AA4488
Also seems to work in the opposite direction (SFO -> PIT):
https://www.google.ca/flights/#searc...9-PHLSFO0AA759
Interesting these don't book into basic economy so you should be earning 100% mileage on AA. A number of dates seem to be available for this deal including same day turn around. Arguably one of the best domestic deals of the year so far.
Safe Travels,
James