Following a positive drug test for banned substances including anastrozole and clomiphene, Chael Sonnen has announced his retirement after 17 years. "I am officially done, I will not set foot in that octagon again" said Sonnen on Wednesday night's UFC Tonight, where he also serves as a host. Sonnen is best known for being the first man to take UFC legend Anderson Silva into deep waters, and for being a brash, trash talking master on the mic. Originally slated to settle a long-running feud with Wanderlei Silva at the upcoming UFC 175 event in July, his opponent was changed recently to Vitor Belfort when Silva ran out on a surprise drug test. The match with Silva was the culmination of their feud on the Ultimate Fighter Brazil 3, where the two served as coaches, and wound up in an on-set brawl. The Belfort fight was just as intriguing, and could have led Sonnen to a fourth UFC title shot. Instead, he'll finish his career 1-3 over his last four fights, though it should be noted that of the three losses, two were against champions Anderson Silva and Jon Jones, and the final loss was against former champ Rashad Evans. His last win came last August against another MMA legend, Shogun Rua.Sonnen explained on UFC Tonight that he was on the substances as part of his transition off of the previously banned TRT, a treatment he has stated he was on due to the condition hypogonadism. Anastrozole and clomiphene were to ease himself off the TRT and jump start testosterone production. The substances are not illegal, and are not the same as anabolic steroids, but they are banned from competition by the NSAC. Sonnen owned up to not notifying the NSAC that he was on the substances, saying it was something he should have done. To quote Sonnen, "the rules are the rules, and it is up to the athlete" to disclose the information. However, he stated that the drugs in question, which also included hCG, have helped him overcome fertility issues, and also announced that he and his wife are expecting their first child. It's been a crazy ride; watching Sonnen in and out of the cage. "Guys, I've had a great time" said Sonnen of his career. One has to agree - watching Sonnen has been akin to riding a roller coaster in the dark. Sonnen has a hell of a career ahead of him in the broadcasting realm with Fox, and if that fails, there's no doubt he could go the pro wrestling route. Or as Dana White suggested, take over the UFC itself. Chael's gone from the cage, but you may just see more of him than ever.