New Zealand paceman Tim Southee faces a race against time to be fit for the World Cup after dislocating and fracturing a bone in his right thumb on Friday.
Less than three weeks before the start of the World Cup in India, Southee suffered the injury while dropping a catch off England's Joe Root in the final one-day international of the four-match series.
Root, who was on eight at the time, edged Ben Lister to Southee in the slips.
He immediately looked to be in pain and left the field to go for a scan, failing to return.
"An X-ray has confirmed that Tim Southee dislocated and fractured a bone in his right thumb while attempting to take a catch in the 14th over of the first innings," said a New Zealand team spokesman.
"A timeline for his recovery will be established tomorrow when he undergoes further assessment."
New Zealand begin their World Cup campaign against defending champions England in Ahmedabad in the opening game of the tournament on October 5.
Southee, 34, named this week in an experienced New Zealand squad for the tournament, had taken 214 wickets in 156 ODIs before Friday's match at Lord's.
He bowled four overs for 29 runs on Friday as England scored 311-9 in their 50 overs.
New Zealand captain Tom Latham, speaking after England won the match by 100 runs to take the series 3-1, described Southee as a "resilient character".
"He's a massive leader among the group and he'll be assessed over the coming days when we get back home to see how bad it is," he said.
"Luckily we do have a little bit of time leading into those first couple of games so we'll know a little bit more over the coming days.
"He's a pretty resilient character so I'm sure he'll be doing all he can to be on the plane ready for that first game."
Seamer Lister suffered a hamstring strain, though he was able to bat.
Latham said he would know more once the bowler had a scan.
"Fingers crossed it's not too bad for him as well," he said.