Tuivasa-Sheck's current contract with the Warriors runs out after this season.
The Aucklander is on the UFC 219 card on New Year's Eve in Las Vegas, a rare achievement for a Kiwi.
Reid Harker won't do it on his own though, with a Kiwi legend guiding him off the track as well.
Sir John filled the roles of a rugby player and headmaster in his life, but what he did for those around him in those roles is what set him apart.
The All Blacks have named a strong line up to face Manu Samoa but are still keeping tabs on the Lions.
The trio could be in line to start a Test match together when the All Blacks take on Samoa on Friday.
1 NEWS understands Parker will work solely with Higgins after DUCO's split.