Test coach McCullum and Test captain Stokes have transformed the red-ball team, and secured an eye-catching series victory over New Zealand, during which they chased down some formidable targets with fearless, attacking batting.
Rashid is an essential part of England's one-day and Twenty20 plans but last appeared in the longer format three-and-a-half years ago.
He has not played at first-class level since, settling into a white-ball specialist's contract at Yorkshire, but the idea of bringing the 34-year-old back into the fray was floated by McCullum shortly after his appointment earlier this summer.
McCullum has already persuaded Moeen Ali to reverse his Test retirement, with an eye on this winter's tour of Pakistan, but appears to have a tougher job on his hands with Rashid.
Speaking ahead of England's first Twenty20 against South Africa in Bristol, the start of their fourth limited-overs series this month, he said: "My mindset has stayed the same. A lot has got to happen for me to play Test cricket.
"You've got to have that communication with the coach and captain, and you've got to sit down and see where I'm at. Let's see what happens there, but that's a long way away.
"It's not quite easy for me to say 'yes' and 'no'. I take it a game at a time, a day at a time. But at the moment I'm not thinking about that, I'm only thinking about white-ball cricket, because that's what we've got ahead of us.
"Cricket's coming thick and fast. This series, then The Hundred, T20s in Pakistan…there's a lot of cricket to be played in the meantime and a lot can happen in terms of form, how someone feels, injuries, how the body feels, the mindset."
Like so many leg-break bowlers, Rashid has not always been treated especially sympathetically by England and his return of 60 wickets in 19 Tests, at an average approaching 40, feels like an unfinished business.
But while Rashid has modest returns in whites, there is no question that he is the man South Africa's batters will be most wary of when they line-up at the Seat Unique Stadium.
It is tempting to wonder whether McCullum and Test skipper Stokes would be able to unlock his best form with their proactive approach, but the idea of long days and mammoth spells could be a deterrent for a player who has battled long and hard with shoulder problems.
"That's what you have to sign up for - those long days where you can bowl 30 or 40 overs," Rashid added.
"That's something I've got to bear in mind, especially with my shoulder. I haven't bowled long spells in a little while."
England were joined at nets last week by 17-year-old Leicestershire leg-spinner Rehan Ahmed, the under-19 international who is on the up after securing a Hundred contract with Southern Brave earlier this year and a maiden Lions call-up this month.
Rashid, himself a teenage prodigy when he first broke through at Headingley, worked long and hard with the newcomer and was impressed enough to consider him not only a potential successor but also a possible team-mate.
"Playing for England together? That would be nice. It would mean I'll be around for a couple of years!," he said,
"Who knows? He's 17 and he's definitely got a bright future ahead of him if he keeps working on his skills. He's a confident kid as well, so hopefully he'll have a good career.
"Hopefully if I'm around at that time I can pass on my experiences, not just for Rehan but for anyone coming through, on the mental side of the game."
Jonny Bairstow could make his first T20 appearance of the year for England on Wednesday, but was seen nursing a swollen left knee with ice packs and bandages and will need to get the all-clear, while pace bowler Richard Gleeson also has the chance to firm up his spot after making his debut against India.