Williams chief technical officer Paddy Lowe has confirmed the Grove outfit will test Robert Kubica and Paul di Resta "in the next few weeks", following speculation that both are being considered as team-mates to Lance Stroll.
Kubica has been out of the sport for more than six years following a rally accident in which he sustained a serious injury to his arm, however the Pole has been targeting a comeback and completed three tests for Renault before the French team opted to sign Carlos Sainz instead.
Meanwhile Di Resta stood in for an unwell Felipe Massa at the Hungarian Grand Prix earlier this year, but prior to that hasn't raced in F1 since 2013, holding the position of Williams reserve since then whilst competing in the DTM series.
Both will be evaluated by Williams in October or early November, confirmed Lowe.
"You're correct, we will test those two drivers," he replied when pushed on the subject.
"We won't give away any information around what we do within those tests – that's a private matter for us."
Lowe insists other drivers are being considered, with Massa and Pascal Wehrlein thought to be in the mix.
"I would stress that that doesn't mean they are the only drivers under consideration; we're considering quite a large range, of which they are only two possibilities."
