Down have been promoted to Division Two with Longford conceding their final game against Cork leaving the Ulster side confirmed in second place.
Longford's withdrawal means only Derry can draw level on points with Down, who are two points clear in second place.
However, even if they both end on nine points Down would be promoted with their win over Derry in February giving them the superior head-to-head record.
Down finish at Louth on Sunday while Derry face Offaly.
A win for Longford over Cork would have opened the possibility of three teams finishing on nine points - in that scenario the side with the best scoring difference would be promoted.
Down were awarded two points after their scheduled game at the weekend was cancelled as Leitrim didn't travel because of Covid-19 concerns.
Leitrim GAA released a statement confirming the decision to concede the fixture, attributing it to "the greater health situation" and expressing the hope that they can field a team against Tipperary in their final league fixture.