The original game on Friday 27th September was postponed after heavy rain waterlogged part of the Finn Park pitch.
It means Harps will play five games in the fourteen days in October.
The first is this Saturday 1st away to Galway Utd, that will be followed by Sligo Rovers at The Showgrounds on the Tuesday 4th, Harps host Bray on Friday 7th, Pats on Tuesday 11th and then away to Cork at Turners Cross on Friday 14th.
Elsewhere, with Cork City and Dundalk contesting the SSE Airtricity League title, the Lilywhites game against Sligo Rovers and Cork City's trip to Galway United has been pushed back by 24 hours.
Both will now take place at Saturday, October 8th with kick-off at 7pm.