Toto Wolff has said that he still will not designate Valtteri Bottas the 'number two' driver behind Lewis Hamilton.
While Hamilton completed a victory hat-trick and pulled out a 28-point advantage over Ferrari's Sebastian Vettel in Singapore, Mercedes teammate Bottas has struggled recently.
"Yeah, Valtteri has been a bit lost," agreed former F1 driver Mika Salo, speaking to Finnish broadcaster MTV.
"It's difficult to know the reasons - maybe it's just been hard for him to set up the car. Or maybe it's starting to show that Hamilton is more familiar with the car concept."
With Bottas now lagging in the championship and off the pace, Salo said that team orders are not an issue "because Lewis is simply faster".
When asked if Mercedes will put their full weight behind Hamilton for the rest of the championship, team boss Wolff answered: "I think it's clear that Lewis's chances of winning the championship are higher than Valtteri's.
"As before, we will assess the situation, but the situation becomes clearer after every race.
"I don't want to say that one driver is the number one, because it could affect the motivation of the second ... I mean the other, driver."
The championship continues next weekend with the Malaysian Grand Prix.
