“We are up against 150 million (euros),” Hulkenberg’s manager Werner Heinz told Bild newspaper.
Hulkenberg told Sport Bild: “I have never ruled out staying at Sauber.”
World champion Sebastian Vettel agreed: “Nico has absolutely earned his place in formula one.”
It is believed Sauber will retain the improving rookie Esteban Gutierrez, who has links to important Mexican backers.
“I feel very confident that I will stay in F1 next year,” he is quoted by Brazil’s Totalrace in Abu Dhabi.
The other seat, however, was reserved for the teen Sergey Sirotkin, who is a part of Sauber’s crucial Russian rescue deal.
Team boss Monisha Kaltenborn, however, said on Thursday that the deal could include some flexibility when it comes to Sirotkin’s driving role.
“I think we will find out fairly soon whether he is ready for formula one,” she is quoted by f1news.ru.
“It is an important step and it should not be underestimated.”