Rugby World Cup 2015 - Wynne Gray: Read's impact in Cardiff will be closely monitored

New Zealand All Blacks captain Kieran Read takes on the Tongan defence, during the Pool C match between New Zealand and Tonga. Photo / Brett Phibbs

A couple of years ago, Kieran Read's surge through the world rugby ranks was irresistible.

Every time he wore the black jersey he seemed to produce special moments around the other tasks he dealt to as the nation's premier No8. He was both brutal and delicate, imperious and unselfish as he roamed world rugby fields.

His decisions were strong and his production was a repeat collection of high quality.

Attack or defence, it did not matter. Read did not shirk or favour one above the other. His instincts were usually on the money and his intent was all about the collective rather than individual glory.

That was 2013 when World Rugby also hit the mark and Read was player of the year.

New Zealand was blessed with another No8 to rank alongside Brian Lochore, Murray Mexted, Wayne Shelford and Zinzan Brooke.

Around that time, Read's impact and presence was becoming more valuable to the All Blacks than Richie McCaw and it was easy to see the leadership succession plan.

Several years on and that pattern has been discontinued.

Concussion bit into Read's performance last year and there has been another incident this season. His form has dipped, his confidence has taken a bang and his individual skills have not been at his usual level.

If Read's form has not been a lengthy discussion topic around the selectors' table, it should have been, especially after his patchy game and yellow card against Tonga.

He has played 81 tests including three starts and one match off the pine at this World Cup and like a few teammates, made an ordinary impression.

The issues for the selectors would have been multi-layered. Read is the deputy leader to McCaw and a guiding force among the group and if he was replaced and the team prospered, it would be hard to recall him later in the tournament.

If Read was overlooked who replaced him? Victor Vito is the next in line and a magnificent athlete who has brought his work rate up in line with his attacking skills with a slight uncertainty about whether his defence matches that offence.

That and the leadership must have tipped the balance.

Vito got the start at No8 against Namibia and was a sub against Argentina and Georgia but that workload was probably not enough to convince the selectors he was playing at such a level he had to replace Read.

They would have looked at the combinations Jerome Kaino, McCaw and Read had built up and the way they usually brought their united impact to big matches and how valuable that experience was under that pressure.

That's the theory, now for the production.