Canterbury legspinner Todd Astle's international cricket career is poised to receive a major boost with Daniel Vettori set to miss the tour of South Africa.

The Press understands Vettori will not travel to the Republic amid a number of injury and form-enforced changes to the Black Caps, further exacerbating the team's current instability as ructions over the team's captaincy reach a crescendo.

Ross Taylor seems certain to be dumped as captain when the 15-man Twenty20 and test squads are unveiled either today or tomorrow and Vettori, Rob Nicol and Andrew Ellis will all be missing.

The news is better for Canterbury's Dean Brownlie, who returns to the team, while the wicketkeeper battle between Kruger van Wyk and BJ Watling may go the way of Watling.

It is understood Vettori, who is still recovering from a hernia operation and an Achilles tendon injury, has not sufficiently healed and will not tour, instead aiming at the English tour of New Zealand later in the summer for his return.

That is almost certain to mean a second tour for Astle, who played in New Zealand's 167-run win in Colombo last week.

Former Canterbury gloveman Van Wyk's future is uncertain. The Press understands a decision on the van Wyk-Watling choice had not been made earlier this week.

Van Wyk scored a pair in the Black Caps' win in Colombo and averaged just 13.67 in the two-test series, but only two matches ago scored a crucial 71 in India.

He's still seen as the best wicketkeeper, but it is understood Watling is the preferred man.

Watling kept in the current Plunket Shield game in Hamilton against Canterbury and has done a sound job, and at the right time.

He took one straightforward catch and one impressive diving effort in Canterbury's first innings under the eye of New Zealand Cricket's director of cricket, John Buchanan. National selection manager Kim Littlejohn was yesterday at Seddon Park too.

Brownlie will travel to South Africa as part of the test side while his Wizards team-mate Rob Nicol is likely only to go as part of the T20 contingent.

Brownlie has already scored two centuries in the Plunket Shield this season, another for New Zealand A and done everything asked of him by Black Caps management. The 28-year-old was told to work on his game against spin and spent 10 days in India doing just that.

The bouncy South African pitches are much more like the West Australian decks Brownlie grew up on and his game - as much as that of anyone in New Zealand - is suited to the conditions, although the South Africans have the best bowling lineup in the world.

Nicol has done little wrong, but with no chances in the longer form since March could be seen as surplus to requirements. He remains a shoo-in for the T20 side.

Injury has ruled out Canterbury all-rounder Ellis and he is not expected to play again until the new year. The 30-year-old tore his left oblique muscle in the Wizards' five-run T20 loss to the Knights last Friday.

He is aiming to return for the Wizards' T20 matches on January 1 and 3 in Nelson and hopes to be fit by the time the Black Caps' ODI side is named for the latter part of the South African tour.

- © Fairfax NZ News