Williams technical chief Paddy Lowe says newly-appointed reserve driver Robert Kubica has to “earn the right” to obtain a race seat next year.
Kubica lost out to Russian Sergey Sirotkin in his attempts to make a return to the Formula 1 grid seven years after his rally accident.
Although a drive failed to materialise, the Pole secured a role as third driver, and is set to partake in a number of test sessions across 2018.
Asked what was the reason for Kubica being overlooked for the second Williams seat, Lowe told Motorsport.com: “I think, to further put it in a different way, Robert has been on a journey to find his way back to Formula 1, from the trauma that occurred to his arm in the rally accident.
“And all credit to him, it’s required an incredible commitment, a lot of bravery and a lot of dedication to that objective. And he’s on that journey, and I think with us this next year as the development driver that journey will continue.
“Ultimately, it’s not always about what’s missing – it’s a competitive market, to obtain a race seat. There are many more very, very talented drivers than there are seats.
“And Robert would want it no other way. He’s got to earn the right to the race seat, whatever race seats may be available in 2019.”
Following his rally accident in 2011, questions have been asked as to whether Kubica is physically capable of driving an F1 car in a full-length grand prix. Lowe, however, quickly assured that the 33-year-old’s fitness is not an issue and is confident Kubica can be called up as a race substitute when needed.
“He would be fine, we’re very confident of that,” Lowe added. “Otherwise he wouldn’t be our reserve driver, if we didn’t think he was competent to race…
“And not just competent, able to perform well in the race, to race competitively.”
