All Blacks cleared over SBW head knock

However, the inquiry has also cleared the All Blacks of mismanagement over the incident.

In their review of the incident, SANZAAR, in line with World Rugby Player Welfare Standards, "has established there has not been a deliberate failure or an 'untoward incident' pursuant to the terms of participation and as such finds no actions that constitute misconduct".

The SANZAAR inquiry determined the following: "The incident was not identified during the game via the appointed HIA [Head Injury Assessment] specialist, the match day doctor, the team doctors or the match officials.

"The available post-game video confirms ataxia, which would trigger immediate and permanent removal under World Rugby protocols.

"While no process is entirely failsafe, the review panel determined that the missed HIA incident should have been identified during the match.

SANZAAR CEO Andy Marinos stated: "This is an unfortunate set of circumstances given the acute focus and attention we are all applying to player safety and in particular the HIA protocols. NZ Rugby has been proactive in its management of Sonny Bill Williams and we have full confidence in its processes to manage his return to play – as NZR has illustrated with other players such as Dane Coles and Ben Smith this year already. 

"As a consequence, and even though there was no deliberate failure apparent, SANZAAR has taken the opportunity to strongly reinforce World Rugby HIA protocols including video analysis during the game, to all teams, match day medical staff and match officials participating in The Rugby Championship."

"Additionally, New Zealand Rugby has confirmed that Sonny Bill Williams is being managed in line with World Rugby HIA protocols, including HIA 3 and computer neuro-cognitive assessment, and will progress to a graduated return to play if asymptomatic," added Marinos.