'Bottas could be replaced' - Wolff

London - Toto Wolff has admitted it is possible Valtteri Bottas could be replaced at Mercedes by a 'bigger name' for 2018.

Some expressed surprise when it emerged that, despite being praised out of his Williams contract, Finn Bottas has signed only a one-year deal for 2017.

Mercedes chief Wolff admits the team is leaving its options open for 2018.

Dynamic driver market

Marca sports newspaper quotes Wolff as saying: "It is true that the driver market is more dynamic for 2018. Then there are a number of options: young drivers, Sebastian (Vettel), Fernando (Alonso), Valtteri, and more. Valtteri understands this."

Former Red Bull driver Robert Doornbos is more blunt as he assesses the situation in conversation with Dutch broadcaster Ziggo Sport Totaal.

READ: F1 - Bottas' 1-year Mercedes deal explained

Doornbos said: "Bottas is an interim solution. Basically Mercedes is looking at Vettel. Only if Bottas wins the title, or makes it very difficult for Hamilton, will he stay."

Doornbos says Bottas was once "really hot property", but his star faded a little at Williams when "the gap to Felipe Massa was in my view smaller than it should be".

Proving his worth

Wolff, too, admits that Bottas now needs to prove he belongs at Mercedes this year.

Wolff told the French daily L'Equipe: "He must demonstrate that he can fight against Lewis (Hamilton). For us, his personality is perfect, as it was important not to upset the dynamics of the team. Valtteri is not at all political or emotional, but his passion for racing is enormous. It will be interesting to see the dynamics between him and Lewis."

READ: Kovalainen not predicting issues with Hamilton-Bottas pairing

Asked if Bottas can actually beat Hamilton, however, Wolff answered: "It's difficult to say when the new cars haven't turned a wheel.

"Valtteri is an exceptional driver and has the ability to push Lewis as Nico did. We believe in him. But can he beat the best driver currently in F1? I don't know."