Ben Foakes was England’s keeper for the 4-1 series defeat in India, with Bairstow playing as a specialist batter after donning the gloves for last summer’s Ashes.
After the loss in India, McCullum said of the Test keeping position: “We’ll work that out in time. Whatever we decide, we will put the investment and the support in, and try to give the most amount of time for that to be successful.”
Any decisions England take over the Test side this summer will partly be with the 2025-26 Ashes series in Australia in mind.
Along with Foakes and Bairstow, Lancashire’s Salt might come into the reckoning. The 27-year-old has been in blistering form in T20 cricket and is currently the leading overseas run-scorer in the Indian Premier League (IPL).
Another candidate would be Durham’s Ollie Robinson. The 25-year-old, who has experience with England Lions, has passed 50 in all five of his County Championship innings this season.
“No-one will be ruled out,” said Key.
Neither Salt nor Bairstow are expected to keep at the T20 World Cup, with captain Jos Buttler set to take the gloves despite not keeping for part of England’s tour of West Indies in December and again in the IPL.
“He captains very well with the gloves,” said Key. “He’s the heartbeat of the team and the focal point for everyone.”
However, England may need a stand-in keeper and captain during the four-match series against Pakistan, beginning on 22 May, with Buttler due to attend the birth of his third child.
The reigning champions have recalled pace bowler Jofra Archer after a year out injured for the World Cup in the Caribbean and United States in June.
England begin their defence of the trophy they won in Australia in 2022 against Scotland in Barbados on 4 June.
They do so after an awful campaign at the 50-over World Cup in India last autumn, where they were also defending champions but won only three of their nine matches.
But Key denied there was additional pressure on captain Buttler and coach Matthew Mott to oversee a strong campaign at the T20 World Cup.
“When it comes to being a coach and captain, it’s about getting your players playing as well as they can,” said Key. “Let’s focus on that. Don’t worry about the end result.
“Every team wants to win. We have as good a chance as any.”
