Smith and his partner are expecting their first child in mid-December, with the birth likely to clash with either England's second or third Test in New Zealand. "Being at the birth of my son is not something I want to miss," he told the Daily Mail recently. "It will be a memory that I cherish more than any in cricket anyway, so if I lost my place because of it, so be it."

"It's life, right?" McCullum said of Smith's absence. "People have kids and we wish them all the best, to be there and support their partners. At this stage, it looks like Jamie will probably play the first [Test in New Zealand] and may miss the next two. We're not totally sure - it's up to Mother Nature a little - but we know we've got Jordan Cox in the squad here."

It will not concern England that Cox has hardly kept in the last year, as shown with Smith's own selection earlier this summer despite being second-choice behind Ben Foakes at Surrey. McCullum believes from his own experience that New Zealand is "a comfortable place" to keep wicket, and wants to see how Cox - whose glovework he describes as "solid" - fares at Test level.

Cox should make his ODI debut in that series and will have a chance to stake a late claim for a spot in England's squad for next year's Champions Trophy. But it is the prospect of a Test debut later this year that could satisfy his restlessness, and provide vindication for the air miles he will rack up in the first half of the English winter.

"He's annoyingly good at everything he does - particularly on the golf course," McCullum said. "He's one of those guys that you look at and say he's got a high ceiling in terms of talent, particularly with bat in hand. There's a fair chance that he'll get the opportunity in New Zealand, if Jamie does return home, to bat down the order and take the gloves."