At the start of this season, Russell would probably be rated the sixth-choice fly-half at Glasgow. Ahead of him stood Scotland regulars Duncan Weir and Ruaridh Jackson, the hugely experienced Scott Wight, Peter Horne, who had ended the previous season in the playmaker berth, and Stuart Hogg, who had done a couple of shifts in the position for the Lions.
Even just two months ago, Russell was turning out for Ayr in a club match against Gala. To be fair, he had already made a handful of appearances for the Warriors by then, but mostly when Weir and Jackson were absent on Scotland duty. But in the closing weeks of the season, as Gregor Townsend has switched from one player to another as Glasgow's astonishing nine-match winning streak unfolded, Russell has moved to the front of the selection queue.
His place in the side that beat Munster in a tumultuous RaboDirect PRO12 semi-final at Scotstoun last Friday was evidence enough of that. And yesterday we had confirmation that his star really is rising, not just from his selection for Scotland's summer tour, but also from the conviction in his voice when he said he was not just going along to make up numbers or enhance the sum of his knowledge.
Not that he is proclaiming his ambitions from the rooftops. By his own admission, Russell is a pretty reserved fellow, but it has been a matter of some delight to Warriors supporters he becomes a different animal on the pitch, in the heat of competition. "He is a games player," said Glasgow coach Gregor Townsend after the Munster game. "If you put him into the environment where there is a game going on he comes out his shell."
Russell, who took his first steps in rugby with Stirling County minis and then at Falkirk, travelled to New Zealand as a recipient of the MacPhail scholarship last year, and all the reports that came back were good. He was also in South Africa with the Scotland Under-20 squad a couple of years ago. At the age of 21, he is clocking up the continents at an impressive rate, but transatlantic travel will be a new experience.
"I've never been to America before," he smiled, "so that will be another first."
Russell's development in the shadow of Weir and Jackson recalls the emergence of Rory Lawson a few years ago. At the time, the great debate in Scottish rugby centred on whether Chris Cusiter or Mike Blair was the better option as the national side's scrum-half. Then, in a match between Cusiter's Borders and Blair's Edinburgh that was meant to settle the matter, Lawson came on as a replacement for Blair and outshone both of them.
Russell agrees with his club coach's assessment of him as someone who comes alive in the heat of battle. "If I have to talk in front of the boys I'm not really too comfortable doing that," he explained. "But I have a bit more confidence on the pitch than I do off it, if that makes sense. So I find it much easier talking to the boys on the pitch as a group, than talking to them in a team meeting."
So what of his dizzying rise from anonymity to a point where he is favourite to start for Glasgow in the PRO12 final in Dublin on Saturday week and in with a decent chance of coming back from the summer tour - which will also take the Scotland side to Argentina and South Africa - as an international player?
Russell said: "It's an amazing feeling to be called up for your country. It's probably still not sunk in yet, but I'll get there. Two months ago I was playing for Ayr down in Gala, and now to be called up for the summer tour, it's huge.
"With there only being two pro teams in Scotland; if you are starting for one of them then you've got a chance. But Duncy [Weir] and Jacko [Jackson] are both great players so it was still going to be tough."
As it happens, neither Weir nor Jackson will be part of the North America leg of the tour, although both will figure on the trips to Argentina and South Africa. In fact, Tom Heathcote is the only other specialist fly-half available for those first two games and, although Hogg or Greig Laidlaw could also be deployed, Russell's debut looks all the more likely.
He is a pretty relaxed individual in the club environment, but he is not sure if he can take that attitude into the Test arena.
"I guess it will be a different trial for me," he shrugged "I don't know, I just like to chill out and not think about it too much. I sort of keep the situation of the game out of mind and just get down to what I always do, whether it is playing at Ayr or Glasgow. Or maybe Scotland."