Chael Sonnen failed the same random drug test in late May that led to Wanderlei Silva's removal from UFC 175, an ESPN report revealed on Tuesday, which was subsequently confirmed by MMAFighting.com. As a result, Sonnen has been removed from his tentative July 5 bout against Vitor Belfort.
According to Nevada State Athletic Commission (NSAC) executive director Bob Bennett, both Sonnen and Silva were asked by to undergo random drug tests while in Nevada for a recent UFC 175 pre-event press conference. Silva refused the request. Sonnen complied, however two illegal substances -- Anastrozole and Clomiphene -- were later discovered in his test results.
The UFC issued the following statement on Tuesday: "UFC officials acknowledge irregularities in a recent random test. Chael is planning on addressing the matter this afternoon."
Both Anastrozole and Clomiphene are forms of anti-estrogen treatments.
According to Bennett, Sonnen is expected to attend an upcoming commission hearing at a yet-be-scheduled date, where his fate will likely be decided. The 37-year-old veteran was previously suspended by the California State Athletic Commission in 2011 after testing positive for elevated levels of testosterone in his first bout against then-UFC middleweight champion Anderson Silva.
A longtime user of testosterone replacement therapy (TRT), Sonnen intended to compete at UFC 175 without TRT for first time since the NSAC banned the controversial treatment in early March.
"There's a lot of moving parts. I don't have all the answers," Sonnen said on FOX Sports 1 in the immediate aftermath of the TRT ban. "The bottom line is testosterone is out. Now, as it relates to Vitor, I think this was a very genuine and sincere thing for him. Here's the problem that I have: a fighter that said seven days ago, ‘I need TRT or I can't do this,' and then all of a sudden goes, ‘Well, I'll just stop TRT.' I find that very disingenuous.
"I am potentially in that same field. If this retires guys, then it retires guys. The rules are the rules, and the rules need to be followed. Personally, sorry to be long winded about this, but I'm going through this myself, where I've had to stop testosterone with the hope that we can find a new way to gain the results of upping testosterone to stay at a healthy level. If it doesn't work, I may have to stop the sport. And it's as simple as that."
Sonnen is expected to address the situation at 6:00 p.m. ET on FOX Sports 1.
MMAFighting.com will continue to update this story it unfolds.