The French giants will contest their first home match of the 2014-15 campaign at Montpellier's Stade de la Mosson ground because of disagreements with the city's authorities about rent, with future home ties also shrouded in doubt.
The nine-time French champions failed to agree a mutually acceptable rent for the Velodrome - which recently underwent major remodelling - with the club reportedly branding the city’s asking price of £6m per season as too much.
The city is said to want £4m plus 20 per cent on the ticket sales and 8% taxes from the club, but the club's officials have reacted by taking the case to an administrative court.
Marseille mayor Jean-Claude Gaudinis is confident that the matter will be resolved, although he said OM’s threat to play their home games outside of the city was “absurd”.
"This is legally impossible. Besides, Marseille will lose €1.1m (£880,000) in ticket sales to avoid a €380,000 (£300,000) rate. By playing all home games outside the city, they would lose €20m (£15.8m). It's economically absurd," the 74-year-old mayor told L'Equipe.
"The city of Lille is renting its 50,000 seater stadium at the same price while the Velodrome has 67,000 seats. It's cheaper in Marseille."
The Velodrome is one of the stadia that will host six Euro 2016 fixtures and the decision to play their domestic games away from the ground next year has been described as “painful” by the club’s general manager Philippe Perez.
"Everything was done on our side to allow fans to come and support their team at the Velodrome," Perez told the club's official website.
"But the radical position of the municipality leaves us no choice but to take this painful decision.
"It is, unfortunately, our only option to protect the vital interests of OM - we cannot and will never pay what the mayor asks."
Marseille will host Nice 12 days after their fixture against Montpellier in what will be their fourth Ligue 1 match of the domestic campaign.