Russell had been tipped to graduate to the works team in 2021 should a vacancy arise, but he has now been formally confirmed for a third year with Williams, and the Brackley outfit is set to continue with incumbents Lewis Hamilton and Valtteri Bottas.
Esteban Ocon, the other Mercedes protege with an eye on a works seat, will stay with the Renault team next year.
“We are very happy with the line-up that we have,” said Wolff. “Valtteri and Lewis perform well, they get on really well with each other, which is important for the dynamic within the team. The engineers just really appreciate their feedback. That’s one thing.
“On the other side George has a contract with Williams, a three-year contract which runs one more year. Claire [Williams] made it very clear that she sees George as an important asset to the team.
“And from that side one must respect the contractual situation. We knew, George and us, what we were getting ourselves into two years ago. Williams gave George the opportunity to come into F1 and this is why the decision that Williams takes, we respect it very much.
“It doesn’t mean that if George would be free he would find a guaranteed slot within Mercedes. Valtteri and Lewis are our drivers today, loyalty is something very important to us, and we are always looking at the long time picture.
"George is certainly part of the plans for the long-term, but not 2021.”