Mercedes should keep Valtteri Bottas because he is a "good water carrier" for Lewis Hamilton.
That is the view of former F1 driver Marc Surer, who plays down the rumours linking Bottas with the exit door and George Russell with the Finn's seat for 2022 and beyond.
"The rumours about George Russell as the second driver came from England, of course," Surer told Sport1.
"It would damage the team if they changed drivers. Why? Because Bottas is a good water carrier."
In German, the term 'Wassertrager' refers to a job that was done before centralised water supply systems, when someone would collect water from the source and carry it to others' homes.
"He helps Hamilton," Surer explains, "and you can see at Red Bull how difficult it is to find a good second driver. Bottas is the best number 2, the best water carrier.
"He is criticised all the time because he wins a race every now and then, but he has a thick skin. On a good day he is unbeatable and then he can't do it for the next five races.
"He's not a high-flyer - that's why the criticism has been there from the start," Surer added.