Buttler was batting in the afternoon session when he cracked a powerful pull shot straight at the Sri Lanka Board XI’s short-leg fielder, who crouched for cover but could not avoid a nasty blow.
The ball ricocheted to leg-slip and was caught but Buttler’s mind was not on losing his own wicket, with Nissanka clearly in pain as he lay prone on the turf.
England’s medical team – doctor Moiz Moghal, physio Craig de Weymarn and massage therapist Mark Saxby – were quickly on hand to offer assistance, helping place the 20-year-old in a head brace and on to a stretcher before an ambulance arrived to take him to hospital.
Coach Avishka Gunawardene later described Nissanka, who complained of neck pain during the episode, “as stable and conscious” ahead of an MRI scan.
Speaking after stumps, Buttler said: “You always fear the worst, I think. I hit him very hard and straight in the middle of the helmet and luckily the medics rushed straight on and treated him.
“You’re just worried, and that is the nature of it, you don’t mean to cause injury but it is a real unfortunate accident.
“You don’t really care about getting out, you just hope the lad is okay. But we’ve got a great doctor and physio here and they did a good job.”
The final session of the match saw the Board XI decline to post any close catchers, an entirely understandable decision which nevertheless removed an element of tension from the game as Joe Root put the finishing touches to an unbeaten century in a final score of 365-7.
Buttler accepted a certain competitive edge was missing but still rated the evening’s play as an important part of the preparations for next week’s first Test in Galle, when England can once again expect fielders swarming round the bat.
“Perhaps it took something (out of the game) but it is hard for someone to go in there so soon after something like that happens,” he said.
“The guys still had some good time in the middle, whether short-leg is in there or not it is good to acclimatise.”
On a purely cricketing level, the first of England’s two warm-up matches yielded few firm conclusions about the likely composition of the Test XI.
On day one it was hard to pick between Stuart Broad, Sam Curran and Chris Woakes for what is expected to be one seamer’s slot, while the second day saw Keaton Jennings (13) and Joe Denly (25) in underwhelming form in a new-look top three.
Rory Burns’s confident 47 at least marked him out from the pack but even the identity of the wicketkeeper is currently unknown.
First-choice Jonny Bairstow has been injured but returned to net practice on Wednesday, while Buttler, Ben Foakes and Ollie Pope shared the glovework in his absence.
“If I’m needed to keep then I’m looking to keep a lot better than the way I feel I did in the one-day series,” said Buttler.
“I was disappointed with that. I didn’t feel I had rhythm. I’d like another session with the gloves and with the bat.
“I don’t know yet. I’m just preparing as much as I can.”
The County Championship structure will change from 2020 to include 10 teams in Division One, the England and Wales Cricket Board has announced.
The 2019 season will see three teams promoted and only one relegated in order to reverse the current balance of eight teams in the top flight and 10 in Division Two.
Promotion and relegation will then revert to the current two-up, two-down system from 2020. bAn ECB statement read: “While not significantly affecting the ‘best v best’ principle in the top division, this change will provide an appropriate increase in security to Division One teams with a smaller percentage being relegated each season, and a correspondingly increased opportunity for Division Two teams as they will have a greater percentage chance of promotion.”
The T20 Blast will remain in its current format while the county 50-over competition will be played during the same time window as the new short-format competition, details of which are still being confirmed. Overseas players will not be allowed to play in the 50-over competition.
Lancashire leg-spinner Matt Parkinson has been withdrawn from the England Lions squad to face Pakistan A due to a stress fracture in his back.