Dane Coles and Sonny Bill Williams are both rated good chances to start the second Bledisloe Cup Test as their recuperation from head knocks are closely monitored.

The All Blacks have already confirmed one change to their team to be unveiled on Thursday – also because of a head knock – with reserve prop Wyatt Crockett suffering the blow during the 54-34 dissection of the Wallabies in Sydney.

World-class hooker Coles missed that match as a precaution after emerging with head issues following the warm-up match in Pukekohe a week earlier.

All Blacks assistant coach Ian Foster says Coles – who missed most of the Super Rugby season with lingering concussion symptoms – trained strongly on Tuesday.

Foster suggested suggested the 30-year-old is poised to relegate Codie Taylor to the reserves bench in Dunedin on Saturday.

“He trained really well. He had a good week last week actually,” Foster said.

Coles has played just 90 minutes for the Hurricanes since mid March.

Foster said second five-eighth Williams wasn’t pushed at Tuesday’s session but emerged afterwards with no concussion symptoms.

Williams was also symptom-free in the immediate aftermath of the Sydney Test, with the All Blacks admitting they hadn’t seen the early collision which seemingly left the 32-year-old disorientated.

An independent match doctor also missed Williams’ adverse effects.

Sanzaar officials are reportedly investigating the lack of action taken.

Foster said they have since monitored the cross-code star closely since.

“The doc has done what he always does when there is a suspicion of something,” Foster said.

“He was held back a little bit today so we could make sure he was absolutely clear but the signs are really positive.”

If Williams were omitted, his place in the midfield would probably go to Anton Lienert-Brown alongside Ryan Crotty.