The former champion has been vocal about St-Pierre avoiding a fight with other middleweight contenders, saying GSP only sought to fight a vulnerable opponent in the division who happened to be champion.
"My fight at UFC 217 was one of the greatest nights of my life but I now need to take some time to focus on my health", St-Pierre said in a UFC statement.
In an interview with TSN, St-Pierre used his strongest language yet to prepare us for the seemingly inevitable vacating of his title.
Instead, interim strapholder Robert Whittaker (who was elevated to full-time champion) and former champion Luke Rockhold will square off for the 185-pound belt at UFC 221 on February 10 in Perth, Australia.
Robert Whittaker has become the first Australian UFC champion in unusual circumstances, awarded the UFC middleweight championship today after Georges St-Pierre vacated the title.
Rockhold is a former middleweight champion having won the belt at UFC 194 against Chris Weidman and then lost it in his next fight, at UFC 199 against Bisping.
"I feel much better now than before and also it's a lot less blood so it's good". I've always been against performance-enhancing drugs and I did the natural way. There's no easy way.
"I did it the hard way, and it was to gain weight and to maintain my muscle mass, and it was very hard, and it was not healthy".
"I think the body has a natural weight it can perform at its best athletic ability and for me the weight that I am now is my flawless weight". "For me, the weight I have now is my flawless weight (via MMAJunkie)". It was his first fight back in the Octagon since losing the belt to Bisping in June 2016.
This strongly supports St-Pierre's claims that he isn't a natural middleweight.