Speaking to reporters via a video call on Friday, on what would have been a Saudi Grand Prix weekend but for the cancellation of April Middle Eastern races due to the Iran war, the Mercedes driver said his old rival's current frustration was "only natural".
Red Bull's four-times world champion Verstappen has been a vocal critic of the new rules and engines, and what he calls "anti-racing", and has said he will be doing "stuff that makes me smile" in the downtime before F1's next race in Miami in May.
"Formula 1's bigger than any driver," said Russell when asked if he felt there was a danger Verstappen could decide he'd had enough. "(But) you wouldn't want to lose Max because I think we all enjoy racing against Max."
"You do understand and recognise the frustration, but he's achieved what most drivers dream of, winning a championship. He's got four of them. And at the end of the day, I guess you get to a point in life that you want, there's not really much more for him to achieve in Formula 1. He's ticked all the boxes.
"Maybe he can go after the records but knowing him as I do and knowing drivers who have won or achieved similar things, at one point you want to do what puts a smile on your face."
Verstappen is racing a Mercedes GT3 sports car in qualifiers at the Nurburgring Nordschleife this weekend as he works towards competing in a 24-Hour endurance race at the circuit next month.
"The Nurburgring is a special place. There’s no other track like it," the 28-year-old Dutch driver said in March. "The 24h Nurburgring is a race that’s been on my bucket list for a long time, so I’m really thrilled we can make it happen now,"
Russell, who has driven many laps of the historic 'Green Hell' track, said it would put a smile on anyone's face.
"I would love to have that chance to go and race around the Nordschleife," he said.
"But my goal now is to become a Formula 1 world champion. If I have four of them under my belt, I'd probably be doing the same (as Verstappen). He's in a very different stage of his career, and I think you'd understand if he stayed and you'd understand if he went."
Verstappen has been linked to Mercedes in the past, either as Russell's teammate or replacement, and he and the Briton have had an at times explosive rivalry.
In the past, the Dutch driver has been dominant while Russell struggled with a 'porpoising' car that was hard - and painful - to drive. The Briton observed that the cars in previous years were big and heavy but Verstappen was not complaining then because he was winning.
Russell, who won the season-opening race in Australia and is second in the standings after Italian teammate Kimi Antonelli won the next two races, said his was a multi-year deal and he was sure to remain at Mercedes next season.
Verstappen is ninth with a highest finish of sixth and one retirement in the three races.
