From the moment the UFC revealed light heavyweight champion Jon Jones would be clashing with Chael Sonnen in 2013 after the two go head-to-head as coaches on the Ultimate Fighter 17 there was no doubt the rivalry would involve a ton of trash talk considering Sonnen’s reputation for spoken smackdowns. However, during a conference call promoting the pairing, it was actually the 25-year old title-holder who fired off some of the biggest shots.

Jones’ animosity towards Sonnen seemed to in large part stem from the former middleweight contender’s use of testosterone replacement therapy, questioning what sort of shape Sonnen would actually be in if he let nature take its course.

“I think it’s absolutely terrible if you’re going to consider yourself an athlete. TRT would be perfect for Chael Sonnen if he wasn’t competing in one of the toughest sports in the world,” said Jones when asked to elaborate on the topic. “Right now I’m 25, I’m sure I’m not as giddy and happy-go-lucky as I was when I was 20, so if I take a drug at my 25-year-old age and have the energy of a 20-year-old, it just wouldn’t be fair. Everyone would hate me if I did it, but Chael Sonnen gets to do it? I think it’s bull-crap.”

Sonnen was much more tight-lipped when it came to his opportunity to respond, declining to make a comment.

Given the strength of Jones’ opinion on TRT it seems likely this won’t be the last time fans hear “Bones” refer to the controversial treatment. Of course, considering Jones’ 2012 run-in with the law due to driving drunk, and similar remarks in the past, chances are Sonnen will be bringing Jones’ substance-oriented issues up as well. In the end, the two will face off on TUF 17 as coaches and in the Octagon on April 27 to settle the score.