Russell added to BBC Sport: “Toto has made it clear to me that how I’m performing is as good as anybody.
“There is only one driver that you can debate in terms of performance. These are his words and not my words, and that is why I have no concern about my future.
“But there are two seats to every team and I guess he needs to think who are those two drivers.”
Russell’s comments imply that his own contract talks with team principal Toto Wolff are being delayed by Mercedes’ conversations with the four-time champion.
Verstappen refused to directly comment when he was asked on Thursday whether he would be staying with the team next year.
“I don’t think we need to talk about that,” he said. “It’s not really on my mind. Just driving well, trying to push the performance, and then we focus on next year.”
A move to Mercedes could be interesting for Verstappen because of two key factors – current performance and future potential.
Red Bull have lost the performance edge they had from the start of the latest regulations set in 2022, and since the middle of last year their car has generally not been a match for the McLaren.
Verstappen has said on a number of occasions that he does not believe he is really in the title fight this season. He is third in the championship, 43 points behind the leader, McLaren’s Oscar Piastri.
Red Bull have also in the past year lost two major figures who were instrumental in their success – design legend Adrian Newey has moved to Aston Martin and sporting director Jonathan Wheatley is now at Sauber.
McLaren have also signed Red Bull’s head strategist Will Courtenay, although he is currently being held to his contract and will not be able to leave until next year.
At the same time, Red Bull are believed within F1 to be behind Mercedes in their development of the new engine that is required for a major rule change next year, which will see new cars and power-units in F1.
Verstappen might believe that Mercedes, who won the last race in Canada with Russell, would be a more competitive proposition from 2026 than Red Bull.