That has taken an abrupt turn though, with The Mirror reporting McCullum will take over the red ball team - with an announcement possibly set to be made this week.
The 40-year-old is one of New Zealand's most decorated players, having played 101 Tests, 260 ODIs and 71 T20s for his nation - while also leading them to the final of the 2015 World Cup before ultimately falling to Australia at the Melbourne Cricket Ground with the trophy on the line.
A revolutionary wicket-keeper who was known for a positive brand of cricket at every turn, he gave up playing domestic cricket at the end of 2018 and has since coached the Trinbago Knight Riders to a Caribbean Premier League title in 2019.
England have been in the Test cricketing doldrums for some time now, with a failed tour to the West Indies the last straw for Chris Silverwood's rein in charge after a dismal tour of Australia for the Ashes during the 2021-22 Southern Hemisphere summer.
The team are stepping in a new direction on-field too, with Ben Stokes taking over as captain from Joe Root - who remains in the team, but without leadership duties.
A partnership between Stokes and McCullum is believed to be viewed by the ECB as the ultimate way forward, and could see McCullum coach against his country of birth this Northern Hemisphere summer when New Zealand tour England.