The Black Caps have been dealt a major blow on the eve of the series against Australia, with opener Devon Conway ruled out of the first Test with a thumb injury.
He joins paceman Kyle Jamieson as first-choice Kiwis who will miss the Wellington Test, along with Neil Wagner, who retired on Tuesday after being informed he wouldn't be picked in the side.
Wagner's exit means Will O'Rourke will play just his second Test, with a final selection battle between Scott Kuggeleijn and Mitchell Santner based on the Basin Reserve pitch.
Conway suffered the injury while wicketkeeping in the T20 series against Australia last week.
The South African-born star consulted specialists in a bid to be fit for the opening Test starting on Thursday.
"It's disappointing for Devon to be ruled out on the eve of an important match," coach Gary Stead said.
"He's a class player batting at the top of the order for us, and I know he was really looking forward to this series."
Despite plenty of medical assessment on the thumb, the extent of the injury is still unclear, with the Black Caps awaiting a final diagnosis.
On Tuesday, Stead said Conway had trouble holding a bat.
"He's had a bat in his hand a few times. It's not comfortable at the moment," Stead said.
On Wednesday, Black Caps captain Tim Southee confirmed Will Young would replace Conway at the top of the order.
A move would clear the way for Daryl Mitchell, who has been sidelined with a foot injury, to shuffle back into the middle order.
Stead said Henry Nicholls had also joined the squad as batting cover.
"It's nice to have a player of Henry's calibre to call on ... he has plenty of Test experience and covers a number of positions in our batting order," he said.
Further medical assessment will determine whether Conway can join the squad for the second Test in Christchurch.
New Zealand were already coming into the series understrength, with quick Jamieson ruled out long-term with a stress fracture.
The injuries are especially frustrating for the Black Caps, given they have been waiting eight years to face Australia in a home Test series.
Wagner - a long-term irritant of Steve Smith - also won't be a part of the series, after his shock retirement announcement on Tuesday.
The 37-year-old retired after Stead told him he wouldn't be picked for the series against Australia, following a lacklustre performance in the second Test against South Africa.
That has opened the door for O'Rourke, who took nine wickets on his Test debut against South Africa this month.
"What we saw in Hamilton was something special from a young guy," Southee said of 22-year-old O'Rourke.
"He's shown glimpses and there's been something about him ... he's got a lot of attributes that we like.
"I'm sure he'll have a long future at the highest level."
Wagner will still be at the Basin, carrying the drinks and enjoying one last week in the national team set-up.
The fan favourite is sure to be celebrated by Kiwis at the site of one of his greatest acts: claiming the final wicket of Jimmy Anderson to gave New Zealand a one-run victory against England last year.
