England were guarded over whether injury-hit Ben Stokes would bowl against New Zealand when he makes his Test comeback from suspension on Thursday.
Speaking on Wednesday, ahead of the first day-night Test to be held in New Zealand, captain Joe Root said the all-rounder would "play a part" but would not discuss what role he would fill.
"There's still stuff that needs to come out of today to be very sure of that," Root said, when asked whether Stokes, 26, had recovered sufficiently from a back strain to bowl normally.
"But I'm quite happy that Ben will play a part in the game."
Stokes, suspended after a nightclub incident last September which left him facing a charge of affray, was sorely missed by England in their 4-0 trouncing by Australia in the Ashes series.
He returned to international cricket in the recent limited-overs series against New Zealand, which England won 3-2, but has been hampered by back stiffness.
Meanwhile, New Zealand captain Kane Williamson said senior batsman Ross Taylor, who has a Test average of 48.04, had been passed fit after recovering from a groin injury and stomach bug.
"He's good to go so that's great news for us," Williamson said.
"Roscoe has played beautifully every time he's walked out to the crease, the calmness at the crease, the confidence.
"It's reflected in how much success he's had this year. It's important for us as a team that he's there."
- 'Definitely some unknowns' -
The clash at Auckland's Eden Park will be the ninth day-night Test but the first to be played in New Zealand.
Williamson described it as a "slightly unique and an exciting opportunity", but was aware the teams were heading into the unknown.
"There is probably a danger of over complicating some of the finer parts of the pink-ball game," he said, pointing to variable characteristics at different stages of the ball and times of day.
"There's definitely some unknowns. There's a lot of talk about the evening session and the condition of the ball in that time.
"There's heaps of different stats but there's still unknowns. The sample size of pink-ball cricket is fairly small but it's important that you adapt as a change of conditions may happen coming into different stages of the day."
New Zealand are likely to make two changes from their last Test, against the West Indies.
Williamson said Todd Astle would replace Mitchell Santner as the spinner in the side and BJ Watling would return as wicketkeeper.
Watling has recovered from the hip injury which sidelined him from the West Indies' Tests in December.
New Zealand have played only one pink-ball Test, when they lost the inaugural day-nighter against Australia in 2015.
England have played under lights twice in the past year, beating the West Indies at Edgbaston before losing to Australia in Adelaide.
"Having experienced both sides of it I think we're a better side for it," Root said.
"We know generally what to expect throughout the five days at different times throughout each day."