Williams's current drivers have admitted that they are still facing an uncertain future on the grid.
Felipe Massa, the Brazilian veteran, says that he is in talks regarding 2017 not only with the British team.
"Talks began some time ago, and not only with my current team," he said at Hockenheim.
"If it doesn't work and I can't find a team that can have good results, I can finish my Formula 1 career."
Massa, 35, said that only if it is clear that he is leaving F1 will he begin to look at alternatives for 2017 beyond the pinnacle of motor sport.
Also in doubt is the place at Williams occupied alongside Massa by Finn Valtteri Bottas.
"First of all, I'm very confident that I will be in Formula 1 next year. I have not thought of any other option," he told the Finnish broadcaster MTV.
"Decisions affecting me have always happened after the summer break around September, so there's no rush and I'm not worried."
Although supported by Toto Wolff, Didier Coton and Mika Hakkinen, the 26-year-old said that he is more involved in his contract negotiations than ever before.
"For me, it's very easy to speak directly with the team and it's great to be more involved in my own career," he said. "The negotiations don't interfere with my driving in any way."
The 2016 championship continues on Sunday with the German Grand Prix.
