George Russell says the natural path indicates he will be in a Mercedes next year - but he insists he has not been made any promises on his future.
The 23-year-old is entering the final campaign of his three-season deal with Williams and is a member of the Mercedes junior academy.
He impressed as a stand-in for Lewis Hamilton at last year's Sakhir Grand Prix - twice denied a brilliant victory by an error in the pits and then a puncture.
Hamilton and Valtteri Bottas have both signed only one-year contracts with Mercedes, raising the prospect that one, or potentially both seats, could be vacant at the sport's all-conquering team in 2022.
Team principal Toto Wolff has admitted that Mercedes are having to consider their future options, with Hamilton 37 next year and Bottas 32 in August.
"Toto has always given me his word, and always given me the opportunity when he believes I deserve it," said Russell at Williams' season launch.
"They have told me I am part of that future, and whenever that may be in their car again is when they believe the time is right.
"A lot of people think next year is the natural path. But equally things change very quickly in motorsport, especially in Formula One.
"I had a taste of life at the front of the grid last year but I am just focused on the here and now.
"If I perform on track, deliver and continue on the same path and progress that I have been on so far, I guess in the future the opportunity will come. But no promises have been made at all."
Russell's Williams team were earlier forced to abandon their virtual reality car unveiling after they were targeted by hackers.
The F1 team had been due to launch their 2021 machine via an app, which would allow fans to project the new machine into their homes.
Williams have finished rooted to the foot of the constructors' championship for the past three seasons.
Founder Frank Williams sold the F1 operation to US investment firm Dorilton Capital last summer with his daughter Claire Williams relinquishing her role as the de facto team principal.
Williams' new CEO Jost Capito said: "Short-term our goal is to battle on track and make the most of any opportunity, and long-term it is for Williams to be winners again."