Buttler played the last of his 18 Tests in December 2016, against India in Chennai, and since then has largely focused on his white-ball game.
He has remained an integral part of England’s limited-overs set-up and has taken this year’s Indian Premier League by storm with Rajasthan Royals.
But he was still shocked to get the nod to face Pakistan at Lord’s this week.
“It’s a fantastic surprise and an incredible opportunity afforded to me,” he said.
“Any time you turn up here at Lord’s it’s special, and all of those emotions are arriving [yesterday]. It feels like another debut really.
“It wasn’t particularly on my radar.”
Buttler had considered the idea he might never get the chance to wear the England whites again, but despite his globe-trotting Twenty20 exploits never gave up hope of challenging himself at the highest level.
“You always think maybe that race is run and will never happen again,” he added.
“It’s not that you live with regrets, but you definitely miss it.
“To get that call, the overriding emotion was excitement ... I came for a hit here on Saturday. Turning up here on England duty to play a Test match is unbelievable.”
Buttler’s IPL stint means he has not played a first-class innings since turning out for Lancashire against Essex last September.
But he plans to play with a similar – though not identical – freedom that he brings to the short formats.
There were suspicions that he was too reticent, and too eager to prove he had a workable five-day game, on his previous Test appearances.
But with Joe Root as captain and a new national selector in Ed Smith, the tone appears to have shifted.
“It’s going to be a challenge,” said Buttler.
“But from the conversations I’ve had with Joe and Ed Smith it’s very much that they want me to play the way that suits me and in the fashion they believe will get the best out of me in that No 7 role.
“For me it’s about expressing myself, trusting my instincts and allowing that to flourish rather than fight it.
“I’m pretty sure I won’t be opening, trying to slog it in the first six overs, but hopefully I can entertain.”
In terms of bowling, it has been the twin force of Stuart Broad and James Anderson’s record wicket-taking prowess that has underpinned England’s Test exploits for the past decade.
Anderson and Broad’s combined aggregate of 941 wickets have been the powerhouse of England successes at home and abroad.
The vast majority have come in tandem since they were famously paired together by Peter Moores under Michael Vaughan’s captaincy mid-tour of New Zealand in March 2008.
It was at the start of England’s Test trip to that same country 10 years on that Broad spoke with honesty and plenty of characteristic verve about how he had gone “back to basics” at Trent Bridge after his poor Ashes tour last winter and was ready to “do some damage” again.
He impressed many with 11 wickets in three innings over two back-to-back Tests, and observers report that at 31 he is a rejuvenated presence too for Nottinghamshire in the Specsavers County Championship at the start of this summer.
He and all-time national leading wicket-taker Anderson, four years his senior, are both hoping they can still be close to the peak of their powers for the 2019 Ashes and beyond.
As they try to make it there intact, a first stage of the journey begins with the two-Test series against Pakistan.
It was as he prepared to face New Zealand again in Auckland two months ago that Broad spoke so frankly about his form and his future hopes.
Broad said: “I think my action had fallen into a place where it needed repairing, after bowling so much to left-handers round the wicket – in training and in matches.
“I’m in a place now where I feel like I can do quite a bit of damage as a bowler again.”
Anderson for his part knows –whether early-season conditions suit his seam-and-swing mastery or not against Pakistan – that England badly need their evergreen strikeforce to deliver after such a patchy winter.
“We’ve got to start producing the goods more often,” he said.
“We’ve been so inconsistent over the winter and it has cost us.
“We’re more comfortable at home, which helps, but we have to be on our A-game for Pakistan and then for India. It won’t be easy.”