Leg-spinner Todd Astle has been ruled out of the remainder of the Black Caps tour to the United Arab Emirates, and will return home to have his injured right knee looked at by a specialist.
The 32-year-old picked up the injury during the recent New Zealand A one-day series and selector Gavin Larsen said he wouldn't be able to cope with the workload expected in the ODI and test series against Pakistan.
"Despite a period of rest, Todd's knee has, unfortunately, not responded as well as we had hoped," said Larsen.
"The best course of action for Todd is to get home and get it looked at, with an eye to returning in the home summer.
"He worked really hard over the winter and is in some of the best shape of his career, so for this to happen is a cruel blow."
Astle's absence for the test matches paves the way for Auckland Aces off-spinner Will Somerville, who only returned to New Zealand domestic cricket this season, following three years playing in Sydney.
At 34 years old, Somerville could become one of New Zealand's oldest test debutants, behind Herb McGirr who debuted in 1930 at the age of 38.
Larsen said he had impressed the selectors since his return from Australia, and would complement the New Zealand test bowling stocks.
"We've been keeping a close eye on Will and like the look of his all-round game and skill-set.
"He bowls with good control and variation, while his added height means he gets that extra bit of bounce.
"He's also a handy batsman down the order, as he showed with his half-century in the most recent round of the Ford Trophy.
"The test squad already has a leg-spinner in Ish Sodhi and a left-arm spinner in Ajaz Patel, so we think Will's right arm off-spin will balance out the attack nicely."
The first test begins in Abu Dhabi next Friday.