Williams has narrowed their list of candidates to partner Lance Stroll in 2018 to just three, according to Motorsport.com on Saturday with Robert Kubica one of the names mentioned.
It is understood the Grove team has taken over from Renault in their assessment of the Pole, who completed two tests in a 2012 car followed by a third in the 2017 car in Hungary this summer, with the former BMW driver testing the 2014 car.
The French manufacturer ended their interest in what is a much hoped for return for Kubica, after a loan deal for another of their targets, Carlos Sainz, was agreed with Red Bull amid the Toro Rosso/ Honda engine deal.
That has opened the door for a Kubica to look elsewhere with Williams now the highest profile team with a seat not yet secured for next season. Currently, it belongs to Felipe Massa, with the Brazilian signing a one-year extension and putting off retirement at the start of this year to facilitate Valtteri Bottas’ exit.
The 36-year-old is the second name mentioned with Williams pleased with his performances, although the former Ferrari driver admits he has been considering a switch to Formula E.
The final name is reserve driver Paul di Resta who impressed after stepping into the car in Hungary, when Massa was unwell, and drove amicably despite having never driven the 2017 car before qualifying.
The Scot has been off the F1 grid since leaving Force India in 2013 but could arguably offer a longer-term solution for Williams than either Kubica or Massa.
Long shots are believed to be Jolyon Palmer, who was recently dropped by Renault and Marcus Ericsson, who continues to eye a promotion up the grid from Sauber.
However, two names previously linked, Sergio Perez and Fernando Alonso, are now out with the Mexican, who replaced Di Resta at Force India in 2014, re-signing for a fifth season with the team, while Alonso is now expected to remain with McLaren for another year after the Woking outfit ditched Honda for Renault engines.
