Hurricane Jeremy Thrush had been called into this week's wider training squad as cover following Williams' announcement and now finds himself right in the frame.
Dominic Bird, the 2.06m 22-year-old from the Crusaders, is ranked ahead of Thrush and will probably be named on the reserves bench at Eden Park in what would be a baptism of fire - a re-match of the 2011 World Cup final.
Beyond Bird and Thrush, the stocks are extremely low. Chiefs captain Craig Clarke would be a contender but is leaving New Zealand to play club rugby in Ireland after the Super Rugby season, which would probably make him a last resort for Hansen.
For Crusaders coach Todd Blackadder, the three-week test window has for once come at a good time, although he said the injury is a blow for Whitelock.
He said Bird would give a good account of himself if called on by Hansen.
"He's a tough, determined, character. He made the step up to Super Rugby really well and he plays and trains alongside these guys all the time,'' Blackadder said.