Valtteri Bottas' name is the latest to join the 2021 driver 'silly season'.
Reports in Germany suggest that Bottas' manager Didier Coton has been in talks with Renault, who need to replace the McLaren-bound Daniel Ricciardo. Fernando Alonso has also been linked with that seat.
But even Hamilton's next move is under scrutiny.
"It may not be a coincidence that Wolff is now privately involved as an investor with Aston Martin," former driver Marc Surer told Speed Week.
"Hamilton may feel that the great Mercedes era is coming to an end, especially with the budget cap. I can imagine he is doing a lot of thinking.
"But if he stays, then he will try to ensure that Bottas stays too. Personally I would put George Russell in the car. Bottas is a top number 2 but I don't see him as a future world champion.
"If you build up a young driver, you have someone who could take Hamilton's place some day," Surer added.
Another former driver, Timo Glock, said of Mercedes' driver deliberations: "I wonder why they are taking so long to announce the new contracts.
"Mercedes will also be looking at what Daimler is doing, because in the long run they may discontinue the entire project," he told motorsport-total.com.