New Zealand, already jittery about the make up of their World Cup side, got the news they least wanted to hear on Wednesday – that the fly-half Dan Carter was injured and would be missing from Thursday's second pool match against Japan.

To make matter worse for the All Blacks coach, Graham Henry, captain Richie McCaw and full-back Mils Muliaina have been forced to pull out after suffering unspecified injuries. Keven Mealamu will lead the side in the absence of McCaw, who was set to become the first All Black to win 100 caps in the match in Hamilton. Keven Mealamu will captain the side in the absence of McCaw,

Carter was initially named by the coach Graham Henry for his 85th cap in a side which included six changes from the team which opened the tournament with a win over Tonga. However, six hours later it was announced that the 29-year-old had a sore back and would be replaced by Colin Slade, the latest in a line of understudies, who will be playing only his seventh Test.

According to the All Blacks doctor, Deb Robinson, Carter had been recovering well from a back made stiff by damage suffered during that Tonga match. "However, he pulled up sore at an indoor training session this morning so we have made the decision not to risk him and we will aim to have him back fully training next week in preparation for the France Test," said Robinson, whose reference to France must have brought back bad memories for New Zealand supporters.

The last time the All Blacks played France in the World Cup they were undone in the 2007 quarter-final partly because they relied on an injured Carter to steer them through. Clearly Henry, who some still blame for that defeat in Cardiff, considers it not worth risking the health of one of his most influential players.

Against Japan, a team that has won only once in 20 World Cup matches, the removal of a national icon is unlikely to have an immediate impact, but it is yet another unsettling factor for a nation that sees itself as the best in the world but has not been world champion since the first World Cup in 1987.

One of the issues that comes up again and again in the endless television and media coverage here, is the No15 shirt and whether it will go to the exciting 23-year-old Israel Dagg or Muliaina, seen as a favourite of the coach but heading off to Japan and semi-retirement once this World Cup is over.

Henry acknowledged there was an issue on Tuesday when he announced the side. "It's still a contest," he said. "We've got a gentleman who's played 98 Tests and who's played some fabulous rugby for the All Blacks over a long period of time, against a young guy who could be a very, very good player. It's a contest, and that's great for that position."

Henry initially plumped for Muliaina to face Japan but both he and Dagg picked up injuries in training and so Isaia Toeava will wear the No15 shirt instead.

At least there was good news for New Zealand with the return of McCaw's back-row partners Adam Thomson and Jerome Kaino, both injured last month and then considered real doubts for the World Cup.

Their return gives Henry options in what is becoming an increasingly important area – the balance of his team's back row. Carter's return is vital in another, with the All Blacks having limited cover at fly-half, something which became equally apparent for France yesterday when David Skrela went home after injuring himself in the difficult game against Japan.

Skrela's shoulder problems mean the France coach, Marc Lièvremont, has his current No1, although not always a favourite, François Trinh-Duc and the uncapped Jean-Marc Doussain of Toulouse, who will arrive on Tuesday, and Damien Traille, a utility back who many coaches have considered playing at No10 only to think better of it.