Buttler played the last of his 18 Tests in December 2016, against India in Chennai.
But despite becoming a white-ball specialist in the intervening 18 months, he has been included in England's squad for the first Test against Pakistan at Lord's starting Thursday.
It is Buttler's form in the Twenty20 Indian Premier League, rather than English cricket's first-class County Championship that has propelled him back into the Test arena following a run of five successive fifties, including two unbeaten 90s, for the Rajasthan Royals.
Now he is set to bat at number seven in the first of a two-Test series against Pakistan.
"It's a fantastic surprise and an incredible opportunity afforded to me," Buttler told reporters at Lord's on Monday.
"Any time you turn up here at Lord's it's special, and all of those emotions are arriving today. It feels like another debut really," he added.
"It wasn't particularly on my radar."
Buttler, 27, admitted he had contemplated that his Test career might be done and dusted.
"You always think maybe that race is run and will never happen again," the innovative ball-striker added.
"It's not that you live with regrets, but you definitely miss it.
"To get that call the overriding emotion was excitement...Turning up here on England duty to play a Test match is unbelievable."
Buttler has not played a first-class innings sice appearing for Lancashire against Essex in September.
But he insisted he had no plans to radically alter his approach for Test cricket, having been encouraged to play his natural game by England's new national selector Ed Smith and captain Joe Root.
"It's going to be a challenge, 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 number seven role," Buttler said.
"For me it's about expressing myself, trusting my instincts and allowing that to flourish rather than fight it," added Buttler, who averages just over 31 in a Test career that has yielded six fifties.
Asked if playing Test cricket was still the "ultimate" level of the sport, Buttler replied: "Yes it is. And I think it always will be for players of my generation."
Buttler also cited the example of India captain Virat Kohli signing for Surrey to prepare himself for a Test series in England later this season.
"Virat signing for Surrey to get used to playing in England, to play well in Tests, shows that in the forefront of players’ minds, Tests are still the pinnacle."
And Buttler was adamant that Tests remained the measure of a player's worth as he reflected on the career of Kevin Pietersen, the former England batsman.
"It was really interesting when Kevin Pietersen retired, I remember watching Ian Ward speak to David Lloyd (on Sky Sports).
"They were talking about his career, and all they spoke about was his Test match knocks... his hundred against South Africa, his hundred at The Oval in 2005, Mumbai or Sri Lanka.
"He played some fantastic white-ball knocks. I think he was player of the tournament when England won the (2010) World Twenty20 -– but for those guys, it was Test matches they were talking about, and I think people still feel that Test matches are the real true test of cricketers.
"I won't leave with any regrets if it doesn't work out, but I feel like the best players can play all formats."
First Published: May 21, 2018, 6:56 PM IST