Williamson is out for at least the next two matches in the series to rest a wonky shoulder.
Such is Williamson's form that he leaves a substantial hole in the New Zealand batting order. Lefthander Latham gets the job for today, but it won't change the essence of his battle for the No 5 position with veteran Grant Elliott.
"I think it's probably a good thing," senior batsman Ross Taylor said, without wishing any malice towards Williamson. "Kane has been the go-to guy for the last 12-18 months. They want to see these guys under pressure and that bodes well for the World Cup."
However, Elliott wasn't in Hamilton yesterday, due to a family health matter, and is unlikely to play today -- although last night it had not been completely ruled out.
A New Zealand Cricket spokesman said no replacement player had been sought.
Unfortunate as that would be for Elliott as he tries to cement a place in the middle order, it offers New Zealand the chance to experiment with five specialist bowlers.
Wicketkeeper Luke Ronchi would be promoted to No 6 and allrounder Corey Anderson shuffled up to No 5 if New Zealand play three fast-medium bowlers plus two spinners.
Taylor remarked yesterday that if both spinners, Nathan McCullum and Dan Vettori, were to play, it would not necessarily be due to the perceived state of the Seddon Park pitch.
The three seamers used in the opening three-wicket win in Christchurch on Sunday -- Adam Milne, Trent Boult and Mitchell McClenaghan -- all impressed. Tim Southee and Kyle Mills won't be available until later in the series but World Cup backup Matt Henry is with the squad and might get a run.
Sri Lanka had hoped to have key seamer Lasith Malinga available late in the series, as he recovers from an ankle injury. However, captain Angelo Mathews said yesterday it's unlikely Malinga will play before the World Cup.
He has an open mind on a preferred XI for the World Cup opener against New Zealand on February 14 in Christchurch. Getting used to movement off the New Zealand pitches shapes as a key concern.
"We've got to adapt ourselves to conditions," Mathews said. "New Zealand play on the same wicket and we have got to try to outplay them in all departments."
By David Leggat of the New Zealand Herald in Hamilton
