But he was ruled out of Surrey's County Championship fixture against Kent last week with a back issue, and will not feature against Hampshire this week after initial scans returned unclear results. He is due for another scan in two weeks' time after a short period of rest, by which time England will have named their provisional squad to meet the ICC's May 1 deadline.

The identity of England's wicketkeeper will also be up for discussion, with the ICC's new stop-clock and fielding penalties for slow over-rates making it more challenging for Buttler to captain the side while also keeping wicket. Phil Salt took the gloves in the final two T20Is of England's Caribbean tour in December, while Jonny Bairstow is the other alternative.

The ECB has not yet indicated publicly whether it will allow England players to stay at the IPL for the knockout stages if their franchises qualify, which would rule them out of the first two Pakistan T20Is. Buttler, who has recently scored two unbeaten hundreds for table-topping Rajasthan Royals, is likely to miss the start of the Pakistan series regardless while on paternity leave.

England are expected to name their squad on Tuesday morning. They will have until May 25 - the day of the second T20I against Pakistan - to make changes but will be keen to avoid a repeat of the debacle last year that ensued when Harry Brook was drafted into their 50-over World Cup squad at late notice after his initial omission.