Beyond concerns about New Zealand's struggle to dismiss England in the second test at Headingley lies the wicketkeeping fitness of Brendon McCullum.
In a needs-must scenario, McCullum assumed the gloves after B-J Watling was ruled out with a strained left knee.
It's McCullum's first test behind the stumps since playing Australia in March 2010. The New Zealand captain is playing his 77th consecutive test since debuting in March 2004. The first 51 were as keeper.
Extending from his current limited overs work into a test was always going to be a daunting prospect for McCullum's gluteal muscles, not to mention his back and knees.
Tom Latham was an option - he kept against Derbyshire - but it was logical to call on experience to replace Watling in such an important match.