Pascal Wehrlein has said his days at Sauber are coming to an end and that the only option available to him next season is a move to Williams.
Wehrlein is set to be replaced by F2 champion Charles Leclerc in 2018 as part of Ferrari's renewed relationship with Sauber and the German has claimed he has known his fate for quite some time.
"I think my sporting performance now has no effect," Wehrlein told Auto Hebdo.
"The races here and in Abu Dhabi will not be decisive. We will not score points and everyone knows that.
"I would say that Williams is my only option for 2018. I was told pretty early on that there would probably be no room at Sauber next year.
"And if I miss next season, then returning to Formula 1 after that would be very difficult."
Wehrlein has scored five World Championship points this season while his team-mate Marcus Ericsson has yet to get off the mark.
However, the Ericsson's funding means he is more likely to stay with Sauber, even though Ferrari would like to add another of their drivers in Antonio Giovinazzi.
"If you do not have any sponsors, it's not possible to organise a cockpit today on your own. It doesn't work," Wehrlein added.
"If my family could pay five to 10 million it would be different, but they cannot."