Another day and another injury blow for the All Blacks with midfielder Sonny Bill Williams having been ruled out of the series against France due to a knee injury.

The 32-year-old Williams aggravated an old injury while training with the Blues and scans have shown that he has a loose piece of bone in the joint which will need surgery.

As a result, he requires surgery and the expectation is that he won't be able to train for at least four weeks. That will rule him out of the entire series, although he will assemble with the squad to continue his rehabilitation.

His loss is a blow as the selectors probably had him pencilled in to start the first test and no doubt play the bulk of the series at No 12.

The concern about his unavailability is heightened as his probable midfield partner, Ryan Crotty, is also battling as he hasn't overcome concussion symptoms he incurred playing against the Blues a few weeks ago.

Crotty and Williams are the two most senior midfielders in the squad, so the selectors will be hopeful they don't lose both men.

Now that Williams has been ruled out, it opens the door for the in-form Ngani Laumape to potentially have an extended run in the No 12 shirt.

If Crotty is ruled out, then it is probable Laumape will be paired with Anton Lienert-Brown at centre.

The selectors may well be eager to give the impressive Jack Goodhue his first taste of test football at centre but they would be wary about partnering him with Laumape given their collective lack of experience.

It is probable that the selectors will call in a replacement for Williams - especially with Crotty not certain to be fit either. That would likely see Matt Proctor and Rob Thompson come under consideration.

Ideally the coaches would have called up Charlie Ngatai who continues to be a hugely effective and high impact contributor for the Chiefs. But he's off to France at the end of Super Rugby and therefore not a long term prospect.

Confirmation of their midfield plans will come on Monday.