Toto Wolff says he has no "plan B" in the event Lewis Hamilton does not sign a new contract with Mercedes beyond 2023.
Seven time world champion Hamilton, 38, has indicated he is keen on inking a new deal, but there have been rumblings Mercedes is reluctant to sign up for similarly lucrative terms with the Briton.
"Perhaps I sound naive," Mercedes team boss Wolff is quoted by Corriere dello Sport, "but I find it hard to think of a plan B if Plan A is still my favourite.
"I don't want to enter into conversations with other drivers because I'm happy with the ones we have. At the moment, there isn't a plan B.
"There's only Lewis," he insisted.
According to insiders, the delayed discussions are more about Hamilton's reluctance rather than Wolff's - despite the fact that the 38-year-old driver sounds keen to stay with the German marque.
Some believe Hamilton is unhappy with the request that he take a pay-cut rather than a pay-rise.
"I think he will tell us in advance what he wants to do," Wolff said. "I don't think Lewis will come to tell us that he is leaving overnight.
"The drivers of course have the right to make such decisions, but he will not abandon us like that. But at that point, if you think you are a team coveted by others, the right solutions will present themselves."
