Sergey Sirotkin is set to complete Williams' driver line-up for 2018 within the next 10 days, according to BBC Sport.
The Renault reserve driver suddenly emerged as an option for the drive when the Enstone team allowed him to join Williams for the post-season Pirelli tyre test in Abu Dhabi.
And, while all eyes were on Robert Kubica – the then strong favourite to partner Lance Stroll next season – Sirotkin also impressed Williams and became the leading contender soon after when it was revealed the Russian could effectively outbid Kubica for the seat with his superior sponsorship deal.
It has been widely reported that Sirotkin would bring another £13m to the Grove team, who are already heavily financed by the Stroll family, and the contract, believed to be two years, is closed to being signed.
— WILLIAMS RACING (@WilliamsRacing) January 4, 2018
Kubica tried to strengthen his claim for the seat by enlisting ex-Williams driver Nico Rosberg as his new manager, but Sirotkin's confirmation would close the last door that Kubica had available to him in order to seal a return to Formula 1.
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