Georges St-Pierre announced last month that he would be vacating his UFC welterweight title and take an indefinite leave of absence.
At the time, St-Pierre said he just needed to step away from the stress and pressure that accompanied the fighting lifestyle. But on Tuesday, St-Pierre said that UFC's decision not to support him in his effort to involve the Voluntary Anti-Doping Agency in the sport's drug testing was one of the factors that led him to step away from the sport.
"It bothered me greatly," St-Pierre said, according to ESPN. "It was one of the reasons I decided to step aside.
"I tried to change things and unfortunately -- maybe for money reasons, maybe for image -- they were not ready to do that. I tried in a very diplomatic way and it didn't work, so it's unfortunate, but I believe it will happen sooner or later."
Before fighting Johny Hendricks last November, St-Pierres invited his competitor to test under VADA's voluntary program. After learning that St-Pierres wasn't paying the bill -- VADA was -- Hendricks decided not to for fear of St-Pierres relationship with VADA.
Hendricks has never tested positive for a banned substance after numerous tests, including the Nevada State Athletic Commission's before his bout with St-Pierres.
"We've made it clear, through presentations at various athletic commissions, that we advocate for the most rigorous drug testing possible," UFC CEO and co-owner Lorenzo Fertitta told ESPN.com. "We've actually advocated for harsher penalties for PEDs.
"Maybe Georges didn't understand the level of drug testing Nevada was doing. They are the ultimate authority that handles drug testing, medicals and everything else -- and they are very capable."
St-Pierres, 32, has a career record of 25-2. He has not indicated his future plans with regard to his fighting career.