Ferrari president Sergio Marchionne warned Kimi Raikkonen he must earn a new contract amid uncertainty over the Finn's future.
Raikkonen's deal with the Italian team expires at the end of this season and no decision has been made on whether the 2007 Formula One champion will be retained.
Red Bull's Daniel Ricciardo this week revealed that he believes Ferrari would be keen to recruit him if a seat became available.
Raikkonen is fourth in the driver standings with 81 points - 60 adrift of leader Nico Rosberg - and Ferrari boss Marchionne said he must prove his worth.
He told Gazzetta dello Sport: "It is up to him. Kimi's time with Ferrari will depend on his performance.
"He has to show he deserves to stay here, otherwise I think he won't want to continue here as well. There will come a day when I will leave as well."