A swift change would open the door early for George Russell, the 23-year-old Brit who is favourite to take Bottas’s seat in 2022.
Bottas, whose confidence looks shot, is in his fifth season with the team, during which time he has won nine races to Hamilton’s 44.
Mercedes are losing faith in Valtteri Bottas, who may be replaced before the end of the season
He has finished third, fifth, second and second in the drivers’ championship in a mostly dominant car.
After a disappointing race in Portugal, when he finished third starting on pole, an engineer at Mercedes, speaking anonymously, said: ‘There is some unrest at the factory about Valtteri.
‘He is not up to it, which was made clearer by the job we saw Russell do in Bahrain.’
Lewis Hamilton could have a new team-mate with Bottas failing to meet expectations
If Bottas departs then 23-year-old George Russell is the favourite to succeed him at Mercedes
Russell, who drives for Williams but is part of Mercedes’ young driver programme, stepped in for Hamilton in the Sakhir Grand Prix last December, when the world champion went down with Covid, and would have won but for a botched pit-stop and a puncture.
Impetus to ring the changes is provided by the keenest fight for the constructors’ title for some time, with Red Bull’s pace and partnership of Max Verstappen and Sergio Perez developing into a real handful for Mercedes.
The decision rests with team principal Toto Wolff, who has remained publicly supportive of Bottas, saying he has ‘nothing to prove’, and is sure to give him further chances to show his value with only three rounds of the 23-race season yet completed.