Former three-time UFC title challenger Chael Sonnen has failed a second, random, pre-fight drug test from the Nevada State Athletic Commission in addition to the one that forced his removal from UFC 175 in July.

Sonnen was originally expected to square off with his opposing The Ultimate Fighter: Brazil 3 coach, Wanderlei Silva, at the event, but Silva was replaced by former UFC champion Vitor Belfort. However, following the original failed test earlier in the month, Sonnen announced his retirement from MMA.

While the initial positive test revealed the banned antiestrogenic substances Anastrozole and Clomiphene in Sonnen’s system, the second test on June 5 detected the presence of human growth hormone (HGH) and recombinant human erythropoietin (EPO), which boosts red blood cells. Both substances are banned in and out of competition.

The 37-year-old was one of the first fighters to bring testosterone-replacement therapy (TRT) into the limelight after his UFC 117 loss to Anderson Silva. Sonnen was suspended by the California State Athletic Commission following the fight. However, since that time, the treatment has been banned in Nevada and many other states. The Oregon fighter opted to hang up his gloves t the age of 37 with an overall record of 28-14-1, but is still expected to be suspended and fined by the NSAC for his failed tests.

UFC 175 takes place from the Mandalay Bay Events Center on Saturday, July 5. It will be headlined by a middleweight title fight between champion Chris Weidman and former light heavyweight kingpin Lyoto Machida. The night’s co-main event features a women’s bantamweight title fight between Ronda Rousey and Alexis Davis.