Northampton are considering leaving their Franklin's Gardens home if they are not given permission to expand the ground's capacity.
The Saints last year reached agreement to sell part of the site to a supermarket chain to finance a proposed expansion of the stadium's capacity from around 13,500 to 17,500.
But Northampton Borough Council appear set to block any application from the chain to build on the site for fear it will harm trade in the town centre.
Northampton chairman Keith Barwell told The Daily Telegraph: "This could be our last season here because undoubtedly, while we are waiting for the council, we are already having discussions with the banks and have a plan B.
"We would have to decide whether it is worth putting the club into significant debt by paying for the redevelopment ourselves or share a stadium somewhere else.
"If the council want to keep the rugby club in Northampton for at least the next 15 years, they are going to have to show a bit of common sense."
The club have the Milton Keynes Dons' stadium:mk registered as a secondary venue as Franklin's Gardens does not comply with Heineken Cup criteria.