A decision on Root and Stokes will not have to be taken until the new year, given England’s next white-ball assignment comes between Test tours of Pakistan and New Zealand.
But if they are to return in India after Christmas, space will have to be made.
Opener Phil Salt looks the most vulnerable after returning just 95 runs in five innings against Australia. Across the series he faced exactly 100 balls and played 43 false shots.
Salt making way would allow Will Jacks to move up to open, who in turn could be replaced by Root at his traditional position at number three. Jacks has kept that slot warm effectively, with two half-centuries in the series.
Lower down, Buttler will return in place of Jamie Smith – another who will now return to the Test side.
England and McCullum have made no secret of their admiration for the Surrey wicketkeeper but retaining him in the near future does not look straightforward.
One solution, if alternative, would be to make Smith opener and add to those comparisons have been made with Australia great Adam Gilchrist. That would also provide the option of Buttler giving up the gloves to concentrate on captaincy.
Reuniting Ben Duckett, who nailed down one opener’s place with a century in Bristol, with Test batting partner Zak Crawley would be a more conventional solution.