Pascal Wehrlein has declared himself "ready" to step up and become Lewis Hamilton's new Mercedes teammate.
Bosses Niki Lauda and Toto Wolff say that almost the entire F1 grid has offered to replace Nico Rosberg following the new world champion's shock retirement decision.
Yet Speed Week quotes F1 legend Gerhard Berger as saying: "For me there is only one candidate - Pascal Wehrlein.
"The experienced drivers are all under contract, and I believe that if you choose to work with new talent, as was the case with Max Verstappen at Red Bull, then you have to promote your junior."
Also linked with the seat are drivers like Nico Hulkenberg and the Wolff-managed Valtteri Bottas, but Berger said that he would not advise Mercedes to break those sorts of contracts.
"It would be different if you could get an [Fernando] Alonso or [Sebastian] Vettel," said Berger.
"But if not, then I would clearly prefer my junior driver Wehrlein and give him a chance. Otherwise, the whole programme does not make any sense."
Mercedes team chairman Lauda, however, is not so sure, admitting: "Hiring a youngster is a risk and we don't know how strong he would be".
German Wehrlein, 22, made his debut for Manor in 2016 and was quoted by DPA news agency as saying in London: "One season in Formula 1 is not much, but I feel ready for the job.
"But I'm sure Toto Wolff's phone has been running hot since Friday."
Wolff, meanwhile, said that Mercedes's other junior, 2017 Force India driver Esteban Ocon, is also an option.
"Our advantage is that our juniors are both 3D-scanned as substitute drivers and included in the chassis design," he said.
"It would be exciting to have one of them in the car.
"But of course we have a variety of options. We will look at all the contracts and make a decision in the next days."
The 2017 calendar is due to get underway in March.
