Vettel's deal with the Italian team is set to expire at the end of 2017 but him remaining with Ferrari is not a foregone conclusion.
Vettel has been linked with moves to both Mercedes and Red Bull, although either switch is highly unlikely.
"With Vettel it doesn't make sense to talk about renewal now," Marchionne is quoted by the BBC. "We must first understand if he feels comfortable with us in 2017."
Marchionne added that a big part of whether Vettel will be "comfortable" depends on whether Ferrari can provide him with a competitive car.
"We must give him a winning car, otherwise talking about the future is useless," he said. "We know Vettel wants to win with us. Can we guarantee it? In return, he must drive with composure, be more calm, less agitated."
Bahrain International Circuit - Winter testing