The Cobblers were due to travel to Adams Park on Saturday but the game was postponed on the morning of the match due to a waterlogged pitch.
Tickets purchased for the initial game will remain valid for the new date.
Northampton slipped to sixth in the table over the weekend after they were left kicking their heels.
Promotion rivals Port Vale, Cheltenham and Exeter all took full advantage of the Cobblers' inactivity with victories, with the Robins and Grecians leapfrogging Aidy Boothroyd's side in the standings.
- Sports & Recreation