Black Caps first-choice wicketkeeper and No5 batsman Tom Latham may not be fit for New Zealand's opening World Cup match against Sri Lanka in Cardiff on June 1.
If he does not recover, Tom Blundell will make his ODI debut.
Captain Kane Williamson confirmed Latham will not play his side's two warm-up matches against India at The Oval in London this weekend and the West Indies in Bristol early next week. Latham is catching tennis balls with his fractured finger.
"We are hoping he progresses nice and quickly and we will have to address it as the days go by," Williamson said.
While far from alone, the Black Caps' preparation for this pinnacle tournament could hardly be described as ideal.
Williamson's men have not played an ODI for three months — their last match in this format the 88-run win over Bangladesh in Dunedin, in February. Since, nine World Cup squad members played various roles in the Indian Premier League; four others featured in three matches against a near full-strength Australian XI earlier this month.
After such extended time apart, pressure is on to immediately come together.
"Having a tournament on the other side of the world where it's a different season and our domestic competition isn't going on is the nature of the beast," Williamson said.
"To a degree, that's the nature of the international game where it's constantly evolving and you're changing formats all the time.
"It's a big tournament on the calendar and preparation has been different for each team.
"There is that individual component but you want to see the team come together as a collective and that's the best way to build momentum into the tournament. That's what every team will be looking to do.
"It's very hard to simulate the exact intensity of a World Cup but we'll get out what we need from these warm-ups. It's really important as a group we gel. We want to be playing our brand, our style of cricket, and focusing on that throughout. For us, it's been great to come together the last few days.
"We haven't played together for a couple of months but the guys are really excited to be back and we're looking forward to the challenges ahead."
Australian captain Aaron Finch is, meanwhile, expecting a hostile reception for Steve Smith and David Warner as the pair return for their first ODIs after one-year bans for their roles in a ball-tampering scandal.
Finch even brushed off suggestions Warner held security fears.
"Not that I'm aware of," said the Australian skipper said. "Since they've come back into the squad over the last couple of weeks, they've been fantastic and contributed as much as they can.
"Once the World Cup gets under way and particularly for games against England and further on after this tournament, with the Ashes, no doubt the crowd will play a part but that's expected. Anywhere you go in the world, the fans play a big part.
"No doubt personally and as an organisation we've got things in place for that but their input and output, with the runs they've been making in the lead-up to this tournament, they've been fantastic."
There were no major surprises as Finch and Indian captain Virat Kohli named England, the No1-ranked ODI side, favourites.
"England have been in great form the last couple of years and, along with India, have been standout performers so you'd have to say England are the favourites," Finch said.
Kohli added: "England are probably the strongest side but all 10 teams are very well balanced. It is a very challenging tournament. I see this as one of the most competitive World Cups in history."
England captain Eoin Morgan attempted to divert pressure.
"I don't think there's anybody head and shoulders above anyone else. It's going to be an competitive."