Rugby: Last chance to find a back-up No9

If there is a decision for the All Blacks selectors still to make ahead of their squad announcement on Sunday, it is whether to include TJ Perenara or Brad Weber.

The situation at halfback is relatively unclear compared with other positions. Aaron Smith is the first choice No9 but the pecking order after that is hard to determine. Tawera Kerr-Barlow, who last year established himself as the preferred second choice halfback, hasn't played since late April due to a broken thumb. He's expected to be passed fit at some stage during the three-test series against Wales, but because of the uncertainty regarding his fitness and form, the selectors may decide Kerr-Barlow is not a playing option for at least the first test.

That will leave them mulling a straight choice between Perenara and Weber. There is a chance they may include both if they rule out Kerr-Barlow.

Typically, the All Blacks have picked three specialist halfbacks but not always. They didn't for the June series in 2012 when they felt they could run with Smith and Piri Weepu and call up the experienced Andy Ellis if they had an injury to cover. The luxury of a domestic series is that they can call up a replacement at short notice.

Picking three halfbacks will come at a cost - the most likely consequence would be having to omit one of either Lima Sopoaga or Damian McKenzie.

So, if it is indeed just two halfbacks to be included, then theoretically both Perenara and Weber have one last chance to state their case this weekend. The door may be slightly ajar - the decision not quite made yet.

Arguably it is Weber who has the most to prove. The onus is on him to force his way into the equation.

Since Steve Hansen took over in 2012, he's tended to stick with the devil he knows when it comes to marginal decisions. The benefit of the doubt - if that's the right way to look at it - goes to the incumbent until there is compelling evidence, one way or another, to make a change.

Perenara has not necessarily advanced his cause in the past few months, but nor has he regressed. His component parts all work and he's a supreme athlete, all of which the selectors already knew. What they haven't yet been able to determine is whether Perenara has improved his ability to package his game into an effective mix.

Decision-making, or at least consistently accurate and decisive decision-making, has been the flaw in his game and it hasn't been obvious in Super Rugby so far that he's on top of that specific fault.

Weber has enjoyed prominent moments and been an effective weapon in the Chiefs' continuity, high-pace game. He's made plenty of casual observers take notice of his running, but some of the detail of his game will have troubled the All Blacks selectors. His passing from the ground can be loose and that matters to the All Blacks where the No1 priority for the halfback is to clear the ball fast and accurately.

If there has been a conclusion to make in regard to Weber and Perenara, it is that the gap between them and Smith continues to look sizeable and may even be increasing.

But Smith can't play 80 minutes of every game. The All Blacks, while they will lean heavily on Smith, need to be confident in the choices they have behind him and on the evidence of this season and his greater experience, Perenara is probably the man whose name will be read out on Sunday.

That could, possibly, change if Weber delivers something sensational in Sydney against the Waratahs, but in all probability the door to the last chance saloon is already half shut.