Bottas will have to prove himself to keep seat - Wolff

Reports that Valtteri Bottas has been given only a one-year contract at Mercedes have given rise to speculation that the team is looking for a bigger name to replace the Finn in 2018 if he can't perform to their satisfaction this season.

Mercedes had to scramble to find a late replacement for Nico Rosberg, who announced his retirement just days after winning the 2016 title. It's rumoured that the Finn's contract only runs until the end of the forthcoming season, with options for an extension kicking in - or not - depending on Bottas' level of performance.

Mercedes boss Toto Wolff has admitted that the 2018 driver market looks much more fluid, with both Sebastian Vettel and Fernando Alonso expected to be free agents and ideal targets for Mercedes to sign up if a boost is required.

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"It is true that the driver market is more dynamic for 2018," Marca sports newspaper quoted him as saying. "Then there are a number of options: young drivers, Sebastian, Fernando, Valtteri, and more.

"Valtteri understands this," Wolff added.

Crucial to the team's decision will be how Bottas shapes up compared with the formidable challenge represented by his new team mate, Lewis Hamilton.

"He must demonstrate that he can fight against Lewis," Wolff told French daily L'Equipe. "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 Formula One? I don't know."

Wolff used to be part of Bottas' personal management team and knows the 27-year-old well, and believes that he will be a good fit at Mercedes.

"For us, his personality is perfect, as it was important not to upset the dynamics of the team," he said. "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."

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Andrew Lewin

Andrew first became a fan of Formula 1 during the time when Michael Schumacher and Damon Hill were stepping into the limelight after the era of Alain Prost, Nigel Mansell and Aryton Senna. He's been addicted ever since, and has been writing about the sport now for nearly a quarter of a century for a number of online news sites. He's also written professionally about GP2 (now Formula 2), GP3, IndyCar, World Rally Championship, MotoGP and NASCAR. In his other professional life, Andrew is a freelance writer, social media consultant, web developer/programmer, and digital specialist in the fields of accessibility, usability, IA, online communities and public sector procurement. He worked for many years in magazine production at Bauer Media, and for over a decade he was part of the digital media team at the UK government's communications department. Born and raised in Essex, Andrew currently lives and works in south-west London.