The French playmaker is being tipped to leave OM over the summer, with Premier League side Arsenal among the clubs said to be interested in buying him. Marseille clinched a spot in next season's Champions League with the victory over Strasbourg, but even that may not be enough to persuade Nasri to stay.
When asked whether he had played his last game for Marseille, Nasri told Canal+: "I dont know. I still don't know yet."
He continued: "If this is to be my last match at the Stade Velodrome, I gave my all. But I am still not sure if it is my last match.
"It (qualifying for the Champions League) isn't the condition for me staying or leaving.
"It is my choice. I have to make my decision before the end of the transfer window."
Nasri, who scored OM's third goal against Strasbourg, is expected to figure in France's 23-man squad for next month's European Championships.
Marseille coach Eric Gerets admitted earlier this week he would not be able to prevent Nasri leaving if the right offer was to come in this summer.