Patel was picked apart by South Africa in the first test. Left arm spinner Martin, a 32-year-old touring novice, would be more appealing against the largely right-hand South African batting lineup.
If coach Mike Hesson and captain Brendon McCullum accept that a spinner must play, Martin has agood case, provided they trust him in his first test to do the job more effectively than Patel managed last week.
The other issue is Chris Martin or Wagner. The 38-year-old Martin got better as South Africa's innings in the first test wore on, and has been a reliable source of wickets against South Africa down the years.
But left-armer Wagner has been lively in the nets this week.
There is a snag. Boult, James Franklin and Wagner - plus possibly Bruce Martin - make at least one too many left armers in the attack.
The team management has been tight-lipped this week. Where often it's possible to pick up a nod, wink or whisper that a particular hand is about to be played, this group hasn't let slip a drop.
The week has been given over to hard work in the nets and trying to imbue themselves with positive thoughts after the second-innings batting of centurymaker Dean Brownlie and wicketkeeper BJ Watling.
Certainly the pitch is likely to help New Zealand's batsmen in their confrontation with South Africa's speedsters. So, too, is the absence of cracking South African seamer Vernon Philander.
The flip side is how New Zealand are going to take 20 wickets to square the series.
That may be a laughable notion after Cape Town, but if they don't go out trying to pursue that objective, there's little point even leaving the pavilion tonight.
For South Africa, the situation is far simpler. Big Rory Kleinveldt will replace Philander and that will be that. Life is good for the Proteas test team right now. But their record in Port Elizabeth, the oldest of the country's test venues, is distinctly ordinary.
"I thought they batted really well in the second innings," Rory Kleinveldt, Philander's replacement, said of New Zealand yesterday.
"Their confidence is quite high coming off their second innings so we have got to be on the money come Friday."
Certainly all the indications are that New Zealand should be capable of a far more resilient performance. If they're not, heaven help them.
SA v NZ
Port Elizabeth, 9pm start
South Africa (likely): Graeme Smith (c), Alviro Petersen, Hashim Amla, Jacques Kallis, AB de Villiers, Faf du Plessis, Dean Elgar, Robin Peterson, Dale Steyn, Morne Morkel, Rory Kleinveldt.
New Zealand: (from) Brendon McCullum (c), Martin Guptill, Kane Williamson, Dean Brownlie, Daniel Flynn, BJ Watling, James Franklin, Colin Munro, Doug Bracewell, Jeetan Patel, Trent Boult, Neil Wagner, Bruce Martin, Mitchell McClenaghan, Chris Martin.
David Leggat travelled to South Africa with the assistance of ANZ
