Medical tests for Waikato No 8 Sione Lauaki will settle the balance of the World Cup squad to be named at Eden Park tomorrow.

The punishing loose forward was booked in for an assessment by specialist Barry Tietjens with the result certain to impact on the last few places in the 30-strong squad.

Lauaki had minor surgery on cartilage in both knees after the Super 14, treatment which removed him from All Black consideration and left him with a late run in the Junior All Blacks. He was returning to full fitness recently when he tweaked his knee again.

His summons to see Tietjens indicates a change of strategy from the All Black selectors about the balance of their forward mix and the start of speculation about the possible All Black casualties.

The Herald understands lock/loose forward Troy Flavell is most at risk in the present squad.

Reuben Thorne was preferred to cover that role in tonight's test against the Wallabies and Ross Filipo is also believed to have impressed the selectors since he joined the squad.

The chances of Flavell or Filipo making the squad for France appears to depend on the medical advice about Lauaki and whether he needs another operation and how long he will take to recover.

Lauaki has been lost to the All Blacks through injury or lack of form since the Grand Slam tour in 2005 when he played the last of his seven tests.

He finished the Super 14 strongly for the Chiefs but surgery then excluded him from the All Black squad.

One line of thinking had Thorne and Flavell in competition for one World Cup place and comments this week from coach Graham Henry, who has been a long-time advocate of Flavell's talent, indicate Thorne has edged ahead to cover lock and loose forward as an impact player.

"We think he has got, going forward, the possibility of covering lock. We used him in that regard last week and we are looking at that possibility in the future," Henry said.

This season, Thorne has started three tests as blindside flanker while Flavell has started three as a lock without quite revisiting his early Super 14 form. Thorne will offer support for captain Richie McCaw and the experience of two previous tournaments.

If Lauaki's prognosis is uncertain, Jerome Kaino may be considered as another No 8 while Flavell or Filipo could get a reprieve if the panel still feels they need back-up for their injury-prone locks.

The All Black selectors are likely to announce 29 players tomorrow with a vacancy left for prop Greg Somerville who is continuing his recovery from his Achilles tendon surgeries and is a strong chance of being deemed fit enough for the World Cup by the August 14 final team deadline.

Around those quandaries, the remaining 20 reconditioned All Blacks will all be chosen barring any injuries tonight.

Doug Howlett will edge out Rico Gear in the battle of the new fathers for the third wing, Conrad Smith and Isaia Toeava have been fingered as the centres for the tournament, Luke McAlister is now rated the best second five-eighths while Nick Evans and Brendon Leonard have earned rave reviews for their impact work.

In the forwards, Keith Robinson will get the green light with Neemia Tialata and a fit Lauaki to round out the 29 plus Somerville. His inclusion would mean half the squad returning from the last tournament in Australia with Thorne and Byron Kelleher making their third World Cup tournament.

Some of the squad will hone their fitness in the provincial championship while the All Blacks are scheduled to hold training camps in Christchurch and Auckland, involving a variety of skills, physical conditioning and matchplay before they depart late next month.