Mattia Binotto on Tuesday answered "no" when asked if he would rule out Lewis Hamilton joining Ferrari in 2021.
But he said keeping Sebastian Vettel in red "is our first choice at the moment".
British media sources are reporting that Hamilton, 35, will begin his talks with Mercedes on Wednesday about a new contract that could be worth up to an incredible $77 million.
At the same time, Binotto said Ferrari's negotiations with quadruple world champion Vettel, whose own contract is running out, have already begun.
"Obviously it is something we are discussing with him and we will continue discussing, but he is certainly our first option, our preference," he said.
"I think we have two fantastic drivers - the best possible pair of drivers in Formula 1," Binotto was quoted as saying by Sky Italia.
"He (Vettel) worked very well in the winter - I think he will do very well this year."
However, Binotto warned that there may not be a fast decision, insisting that Ferrari will focus on "winter testing and the first races" initially.
Vettel, 32, at least appears unlikely to retire.
"I feel young enough," he said. "You spoke about Lewis, he's even older. So that's not a limitation. So yeah, happy to keep going."
It is clear that the German has now lost his clear number 1 status at Ferrari, but Binotto said he is not worried that relations between he and Charles Leclerc will continue to break down.
"They are professionals," Binotto said. "For his part, Leclerc must continue to grow as a driver, and Seb must show that he deserves Ferrari.
"I find them to be motivated and very relaxed, even amongst themselves."
