"We're pretty comfortable where Brendon's at. He's more than happy to sit the odd one out and let Kane take over [as captain].
"Tom is the likely replacement. He can cover any batting position from one to six, but it's likely he'd go to the top of the order."
Rest and rotation tends to generate pangs of anxiety for New Zealand sports fans whose memories recall the policy's use during the All Blacks' 2007 Rugby World Cup failure.
For the New Zealand cricketers, it might present a risk to momentum as the World Cup looms but, given it's likely to be for only one or two games, it could be a prudent measure against staleness.
McCullum had some time off after the wins in Dunedin, including a visit to the Karaka yearling sales to pursue his racing passion. He was due to rejoin the team last night.
If he's omitted today, it's likely he'd return against Pakistan on Saturday to appease the Wellington cricket faithful - perhaps at the expense of Guptill - and Wellingtonian Ronchi might miss the following game in Napier to familiarise Latham with the keeping gloves.
With Elliott resurrecting his place in the starting XI as a batting all-rounder at No 5, Latham becomes the equivalent of rugby's utility.
"We want to give guys time in their roles and Grant has taken those opportunities with his performances over the last few matches," McMillan said.
Elsewhere, Mitchell McClenaghan has played five of the six games, more than any other pace bowler, and Adam Milne could return on Saturday from his side strain after appearing to coast through a fitness session.
McClenaghan might expect a rest soon. Tim Southee has completed only two matches after not featuring in Auckland due to rain and Kyle Mills returned for the second Dunedin game.
Intrigue also surrounds the selection of the spin bowling all-rounder for the coming games. Nathan McCullum and Daniel Vettori have each played nine ODIs this summer - and four this series - although McCullum missed a chance to contribute due to rain at Eden Park.
In the Sri Lankan camp, pace bowler Lasith Malinga trained as he recovers from his ankle injury but will be rested today, according to stand-in skipper Lahiru Thirimanne.
There was nothing hesitant about his power hitting from the middle of the Basin Reserve during practice. One shot cleared the sightscreen and bruised the chest of team manager Michael de Zoysa with a direct hit.
Angelo Mathews has recovered from his calf injury but now has flu and spinner Rangana Herath has returned home to deal with a family matter. He's expected to return next week.
Thirimanne said his team focuses would be on middle order batting and death bowling with the series ledger sitting at 4-1.
