Despite tying down Nasri to a new deal until 2012, the French club have admitted their star player has a clause in his contract that would force them to sell him for £12m.
Marseille president Pape Diouf revealed: "Samir could leave each season, if we receive an offer in between £12m and £16m.
"But we are trying to envisage things from another angle and our aim isn't to weaken our team."
Nasri, 20, has already played seven times for his country and claims he would be open to offers from Europe's top clubs.
He said: "At the moment, I am not thinking about what I am going to do.
"But I will not leave for another French club, that is for sure.
"I will not leave for leaving's sake."