Bottas joined Mercedes just ahead of the 2017 season as a replacement for Nico Rosberg, who shocked the grid with his announcement to retire from Formula 1 after claiming the 2016 Drivers' Championship.
The Finn joined from Williams and it was late in the day, as all other teams had decided their driver lineups for the upcoming season. Bottas was handed just a one-year deal when he signed, with Mercedes motorsport boss Toto Wolff admitting that the team were keeping their options open for next season.
The former Williams driver, however, has impressed since his arrival at the Brackley-based team and provided a good balance with Hamilton. Bottas recorded his first pole at the Bahrain Grand Prix before recording his first win for the Silver Arrows team in Russia. He replicated both the feats in Austria to further continue his upward trend within the team and admitted that he was delighted to remain part of the Mercedes family for at least one more season.
"I am honoured and proud to continue to work with Mercedes-AMG Petronas Motorsport in 2018 and to remain part of the Mercedes family. Together, we continue to grow stronger day by day, and by keeping up our hard work I believe the sky is the limit," Bottas said, as quoted on the Mercedes AMG F1 official page.
Bottas' consistent performance has also changed the stance of the team management with Wolff recently admitting that it was a no-brainer to retain the Finn, who has formed a strong relationship with Hamilton. The delay, however, in offering him a new deal was likely to have been influenced by Sebastian Vettel's delay in agreeing a deal with Ferrari, which he did ahead of the Belgium Grand Prix. Mercedes non-executive chairman Niki Lauda did admit to the team approaching the German over a potential drive with the Silver Arrows team.
Apart from being impressed with the Finn's performances during the first 13 races with Mercedes, Wolff admitted that another reason was the strong understanding and respect that has built up between both the drivers — it is a far cry from the relationship shared between Rosberg and Hamilton.
"We gave Valtteri a big challenge this year: joining the team at the eleventh hour, stepping up to the forefront of F1 and pairing with the sport's best driver as his team-mate. With that in mind, his results have been probably even more impressive," Wolff said as quoted on the Silver Arrows team's official site.
"There have been ups and downs — more ups, fewer downs — and some great highlights like his two race wins in Russian and Austria. Overall, the balance of his performances and his upward trajectory made it a no-brainer for us to continue with him into 2018.
"For our team, the bonus factors are the respect and sportsmanship that have grown between our two drivers. The chemistry and dynamic between Valtteri and Lewis work and are what we need to take the fight to our competitors," he explained.
Source : http://www.ibtimes.co.uk/lewis-hamiltons-journey-valtteri-bottas-continues-finn-agrees-new-mercedes-deal-1639316