"It is not great news. Obviously, the balance that Brendon brings into the squad is undermined by his ability not to keep," Vettori told reporters on the match eve.

"But Pete (Peter McGlashan) has been in pretty good form for the Northern Districts. So we are hoping he can replicate that and it doesn't unsettle the team too much," Vettori said trying to put a brave face.

Asked if McCullum would be fit for the game, the bespectacled 30-year-old captain said he was optimistic. "It is funny with Brendon. We seem to have had a lot of fitness tests with him and he seems to have come through them all. He is a pretty belligerent guy and he wants to play every game possible. I would err on the side of optimism with him but we just have to wait and see just how it goes." Vettori, however, sounded uncomfortable at the prospect of McCullum not playing on Friday.

"Brendon has been in pretty good form in the T20 format. He probably hasn't put his one-day game together in the last little while but if he is not there, it takes the experience out of that top four," a concerned Vettori said.

"Jesse and Martin haven't played a lot of cricket and Ross is starting to find his feet in the international game after 50-odd games," he said.

"Take him out, and you lose his experience and that knowledge of how to chase down scores. He will be a big loss. But we are pretty excited with the way Martin (Guptill) and Jesse (Ryder) are playing. If they have to go out and open the batting, we still have a lot of confidence in them," he added.

Vettori also expressed dissatisfaction with his bowlers' performance in Napier. "We are tying to find the balance between being tough on them and also realising that they have done a pretty good job for a while now. I think they understand where they went wrong and how to rectify that. We are hoping that Napier is a bit of an aberration in terms of our bowling performance. But we need some guys to step up and replicate the form they have shown previous to that game," said Vettori.

"In a five-match series, you need to be at least 1-1 at this point. So we realise how important it is. I suppose we do have a little bit of reputation coming into Wellington for these sorts of games. So we are confident that we can bounce back pretty quickly. It is a ground we enjoy playing at and hopefully all those things move towards a win for us."