Williams is still patiently weighing its options for 2018 with regard to the man who shall be replacing Felipe Massa next season at the Grove-Based outfit.
The main contenders appear to be Paul di Resta and Robert Kubica, both of which were tested in a 2014-spec car recently, at Silverstone and at the Hungaroring.
But Pascal Wehrlein and Dany Kvyat are also in the frame for a seat alongside Lance Stroll next season.
"We’re very unlikely to make a decision in short order," said Williams tech boss and team partner Paddy Lowe.
"We have a number of different options and we’ll take our time with that and let you know when we have an answer."
But Lowe also told Sky Germany that Robert Kubica would likely get a final run - with a 2017-spec car - in Abu Dhabi, at the post-race tyre test scheduled after the season finale.
"Almost certainly we will give him one of the tyre test days after Abu Dhabi," said Lowe.
"This is a subject that’s getting a lot of attention, I notice, but it’s something we’re working on internally so we won’t tell anyone what we’re doing at this stage."
Lowe's main focus is on improving Williams' performance. Under the guidance of the 55-year-old engineer, Williams has initiated changes and a new approach to its design efforts in a bid to iron out the team's inconsistent performance and move itself up the grid.
"We are motivated to make some significant change to really move forward and create a step from where we are," said Lowe of the team's plans for 2018.
"We’re quite optimistic about what we’re doing over the winter."
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