The All Blacks blueprint for Bledisloe Cup redemption has undergone rapid revision after concussion-prone Leon MacDonald was ruled out of Saturday's vital Tri-Nations rugby Test in Auckland.

MacDonald, brought in at fullback as an extra tactical kicking option against the confident Australians, compounded the All Blacks unresolved injury crisis early on Wednesday.

Medical staff considered he had not recovered sufficiently from a head knock sustained late in the Test loss to South Africa in Dunedin on July 12, robbing the All Blacks of one of their most experienced campaigners.

All Blacks management initially said the versatile 56-Test veteran had been rested from last weekend's 34-19 loss in Sydney to allow knee, elbow and groin niggles to heal.

However, team doctor Deb Robinson confirmed MacDonald's real issue was the residual effects from his latest concussion.

"Going to a team meeting he'll feel more fatigued afterwards than he'd normally do, he'd feel a little light headed at training," she explained.

"The symptoms are very minor in nature but clearly he's got a history - we've decided not to risk him."

MacDonald's unavailability is yet another setback for head coach Graham Henry, who on Tuesday admitted he has been strategically outfoxed by Wallabies counterpart Robbie Deans.

How he opts to compensate for MacDonald will be revealed on Thursday, although regular custodian Mils Muliaina is expected to slot back in from the right wing.

Anthony Tuitavake or Rudi Wulf should then come into the starting line-up, unless management chose to replace from outside the squad.

If Henry selects one of his current wings, Muliaina will be the only viable kicking option in the back three though he was reluctant to boot the ball in Sydney.

MacDonald's absence means the Wallabies will continue to punt deep and pressurise the receiver - a tactic that paid dividends at the breakdown.

Who will play halfback and hooker will also be clarified on Thursday, with Jimmy Cowan expected to start despite twisting a knee against the Wallabies.

There is also a question mark surrounding one of the few positives of the All Blacks preparations so far - the return of Richie McCaw.

Although the inspirational captain has apparently trained without difficulty this week, he did express doubts about being able to endure an 80-minute battle at the breakdown against dual opensides George Smith and Phil Waugh.

McCaw has not played since injuring ankle ligaments against England on June 21 and had understandable reservations about his match fitness.

His understudy Daniel Braid illustrated the downside from a lack of quality match play when thrown into the fray in Sydney last weekend - he was subbed early in the second half.

"That's what I'm most worried about," said McCaw.

"For the last 2-1/2 weeks I've been doing a bit of running but that's never going to make up for match play," he said.

"The first game's always tough. Hopefully the adrenaline kicks in and you get stuck in. It'll hurt but you have to get on with it."

Fitness issues aside, McCaw also said it would be difficult to instantly reprise his superb early season form.

"You can't expect it to just carry on, hopefully you can do the job," he cautioned.

Meanwhile, McCaw admitted there had been plenty of soul searching this week after an admission the All Blacks had been significantly outplayed.

"We weren't happy with the forward pack, we were probably beaten in the physical side of things," McCaw said.

"They probably had an edge over us at the breakdowns."

However, the All Blacks had taken a measured approach to training, with soreness and Auckland's miserable weather forcing their hand.

"We could go and bash the hell out of each other all week but the bodies are sore so that isn't going to help a lot," McCaw said, believing a sound mental approach was the key.

"We've just got to make sure we get ourselves in a state of mind where we know last week wasn't good enough and we're going to turn up better. I know the guys can all do that.

"The guys are a bit niggly. They're disappointed with last week and realise what we've got to do."

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