Formula 1 legend Alain Prost has said that it is "a scandal" that Sebastien Buemi is no longer on the grid.
Since losing his Toro Rosso seat, the now 28-year-old Swiss became a top sports car and Formula E driver, and in July helped Pirelli test F1 tyres at Paul Ricard.
Also in July, there were rumours that Renault advisor Prost wanted the French works team to consider Buemi for 2018.
Renault are understood to have decided to pair Carlos Sainz with Nico Hulkenberg next year, but Prost told the Swiss newspaper Blick: "It is a scandal that Buemi is no longer in F1.
"He is still one of the fastest drivers in the world."
The 2017 season continues on Sunday with the Singapore Grand Prix.
