Brendon McCullum has thrown his full support behind the injured Jos Buttler and said he wanted to get England’s white-ball captain enjoying cricket after a period in which he looked “a little bit miserable”.

Buttler will miss next week’s T20 series against Australia with the calf injury that ruled him out of the Hundred and has troubled him since July.

The captaincy will be handed to Phil Salt for the T20 series and Jamie Overton has been called up. Buttler is a doubt for the ODIs that follow, too, so Harry Brook could captain England at senior level for the first time. Brook is Ollie Pope’s Test vice-captain and led Northern Superchargers in the Hundred.

Marcus Trescothick will coach England against Australia, following the sacking of Matthew Mott after two limp World Cup defences – in ODIs in India and T20s in the Caribbean – over the last year. 

McCullum will take over as all-format head coach in the new year, and has extended his contract for two years, until the end of 2027, to take in an extra Ashes series, another World Test Championship cycle and a World Cup in each format.

Turning 34 this week, Buttler’s position as captain was also in some doubt following England’s poor recent performances but McCullum has given a hearty endorsement to a man he believes will retire as “probably the greatest white-ball player England’s ever produced”.

“I’m very confident,” said McCullum when asked if Buttler was the right man to lead England. “When I started the gig with the Test side, Stokesy [Test captain Ben Stokes] and I knew each other, we had a natural respect for each other but I wouldn’t say we were mates. We got on all right but we weren’t mates. What we’ve developed over the last couple of years is a very close friendship.

“Jos and I actually start from a stronger base. We know each other, we’re mates, we have similar styles of play. What I want from Jos is for him to enjoy the next few years. If he was to retire today, he’d go down as probably the greatest white-ball player England’s ever produced. 

“So the opportunity, for the next three or four years, however long he plays, is just to enjoy it. Not to protect anything. Just get the most out of all those guys around him, keep walking towards the danger, play with a smile on his face and try to do something really cool, where you can look back and say, ‘gee, I really enjoyed those last few years’.”

“He’s been a little bit miserable at times… I think he’s not naturally as expressive, as some may be. But, I think he’s done a great job. He won a World Cup as captain. He’s been part of World Cup-winning teams previously as well. He’s an incredibly gifted player. He’s a fine leader. 

“My job is to get the best out of him so that all those that sit in the dressing room feel like they can be 10 foot tall and bulletproof when they walk out to play, and they know that the skipper is going to give them that extra pat on the back and enjoy the ride with them. So it’s a great challenge. I’m so excited about it, and know that Jos is too, which is great.”

McCullum said that it was an easy decision to take over all three formats, and he is “excited” by a “natural regeneration” that is required in the white-ball set-up. However, he added that he hopes Stokes’s white-ball international career is not over.

“When [managing director] Rob Key asked if there was a world in which I could do all jobs across all formats, I had a chat with my wife and then it didn’t take a whole lot of persuading,” he said. “A couple of years ago I didn’t have a whole lot of knowledge about English cricket, relationships, but fast forward two years and I’ve had a great time.

“I absolutely love being in the position I am in. I have a lot more knowledge about the talent that sits in English cricket and the structures and how things operate.

“If we look at the schedule, it is easing. The last two years would have been impossible, hence we went down the split coaches route. Now with it easing – I say slightly – it can have one person in the role. We’ll have to be smart with stepping [down] players and support staff, including myself, but I don’t see it being a problem. I’m happy to be governed by results and be in the gun if things don’t work out.

“There’s opportunities for other coaches to step up and run the team, just like Trescothick v Australia. That’s great, when I bugger off in three years, you want the next group of coaches to be viable candidates and it should last longer than the time you’re there.

“Great talent sits within English cricket and it’s about realising that talent and bringing it together for one common vision.”

England T20 squad: Phil Salt (captain), Jofra Archer, Jacob Bethell, Brydon Carse, Jordan Cox, Sam Curran, Josh Hull, Will Jacks, Liam Livingstone, Saqib Mahmood, Dan Mousley, Jamie Overton, Adil Rashid, Reece Topley, John Turner.

England ODI Squad: Jos Buttler (captain), Jofra Archer, Gus Atkinson, Jacob Bethell, Harry Brook, Brydon Carse, Jordan Cox, Ben Duckett, Josh Hull, Will Jacks, Matthew Potts, Adil Rashid, Phil Salt, Jamie Smith, Reece Topley, John Turner.