Cross-code star Williams will undergo immediate surgery on an old problem which he has aggravated, leaving him unable to train for the next month.

Sonny Bill Williams Kai Schwoerer/Getty Images

Blues medical staff said x-rays showed a loose piece of bone in his knee joint.

It continues an injury-plagued season for the veteran inside centre, who has played just five Super Rugby games because of knee and wrist issues.

The All Blacks are yet to confirm if a replacement will be called into the 33-strong squad, who were to gather on Sunday ahead of next week's first Test against France at Eden Park.

Coach Steve Hansen could be without both members of his likely Test starting midfield, with Ryan Crotty having been sidelined for the last two weeks while recovering from concussion.

Hansen named five midfield specialists in his squad, including Anton Lienert-Brown, Ngani Laumape and the uncapped Jack Goodhue.

Williams' injury also rules him out of Saturday's Super Rugby match against the Melbourne Rebels in Auckland.