Both would dearly love to play every game in the tournament. You can chalk that down now as highly unlikely.
With that probability, the target for both is to be that one spinner. So it's about performing well as an individual, and ensuring, in the nicest possible way, that they are the preferred choice for coach Mike Hesson and captain Brendon McCullum.
Vettori, having got himself fit again and in bowling trim just in time, knows the score.
"We do offer different options and, depending on the opposition, can both bring something to the table," he said.
He has played 276 ODIs starting in 1997 -- when Kane Williamson was just 6 -- and there's not much he doesn't know about the spinning arts.
Offspinner McCullum has played 73 since 2009, taking 52 wickets.
In his pomp Vettori was more attacking, using flight, drift and guile; McCullum has had a more containing role and has been effective.
McCullum is a fleet-footed fielder and handy late innings batsman, as he demonstrated with an unbeaten 25 to carry New Zealand to a three-wicket win in the opening ODI against Sri Lanka in Christchurch on Sunday.
Vettori has been a distinctly useful batsman, although he needs runs right now. Comparing the two, he comes second in the fielding department.
When it comes to Seddon Park, venue for the second ODI tomorrow, however, neither has hit a jackpot in recent years.
In early 2008, Vettori took two for 16 in 6.1 overs against a hopeless England side -- the match best remembered for the bludgeoning opening stand of 158 by Jesse Ryder and Brendon McCullum which rushed New Zealand to a 10-wicket win.
Since then it has been lean spin pickings at Seddon Park, with neither bowler has taken more than one wicket in an ODI there. McCullum has two for 230 off 48 overs; Vettori one for 68 in 15.
Still, challenge is good, McCullum said yesterday.
"It's only beneficial for the team as a whole when guys are challenging for positions," he said. "Everyone's trying to be at their best and put pressure on everyone else. It's pretty much accepted not everyone is going to play every game. There'll be a horses for courses approach and it's a matter of being ready when called upon."
It has been made clear both will get plenty of opportunities in the eight ODIs remaining before the cup -- six against the Sri Lankans and two against Pakistan.
Time to present their best arguments for the cup opener in Christchurch on February 14.
- David Leggat of the New Zealand Herald
