Rather than train with the rest of the squad in Henderson, West Auckland, today, Williams underwent a medical assessment at the behest of his new Japanese club Panasonic.
The former Chiefs' second-five was a late addition to the All Blacks squad due to Conrad Smith's eye injury. He agreed to play two more matches for New Zealand before jetting off to Japan and then the NRL, but that hinges on a medical examination and a green light from Panasonic.
"Panasonic just want him to have some medicals today and that's fine, that's par for the course, and he's gone and done that," All Blacks coach Steve Hansen said.
"[Team doctor] Deb [Robinson] has taken him to get some tests and once we finalise all that we will get the red light or the green light.
"He's not injured, he's had a big season and I suppose Panasonic want to know what they're getting. There's always a risk, he's going to play two games that they didn't expect him to play, so they just want a bit of clarity and that's fair.
"Initially this wasn't on the cards. The playing field for Panasonic has changed and they're just doing their due diligence and sometimes that takes time and everyone's starting to get a bit panicky about it and it's starting to remind me of Richie's foot, really."
Hansen said the All Black squad, most of whom would play 40 minutes against the Counties and Auckland ITM Cup teams in Pukekohe tonight, were getting on preparing without Williams.
If Williams was ruled out, Ma'a Nonu would play at second-five, with Tamati Ellison or Ben Smith considered for centre.
No Chiefs players would take part in tonight's run-out due to their extended season which finished with a triumph in last weekend's Super Rugby final against the Sharks.
Crusaders lock Luke Romano won't play due to his shoulder injury, but will be considered for selection for the All Blacks' first game against the Wallabies in Sydney next Saturday, August 18.
Crusaders props Ben Franks and Wyatt Crockett wouldn't play either, said Hansen. Owen Franks is likely to play at lock for part of the run-out.
