LAS VEGAS — Former UFC Light Heavyweight champion Jon “Bones” Jones had his temporary suspension extended by the Nevada State Athletic Commission after it was revealed that the fighter recently tested positive for two banned substances.

Jones tested positive for clomiphene, which is listed as an anti-estrogenic substance on the banned list, and traces of letrozole, an aromatase inhibitor, which works to prevent the synthesis of androgens such as testosterone into estrogen, according to a report from ESPN. Jones provided the out-of-competition sample on June 16.

The UFC star defended himself to a fan on Twitter on Monday, saying “you’re absolutely right man, I learned that myself over the last week. But it doesn’t mean you actually took steroids.” He also tweeeted “don’t write me off just yet, I know in my heart that I’m not a cheater. I trust in the system to help me prove it.”

Jones was pulled from a light heavyweight championship fight against Daniel Cormier just three days before UFC 200, which took place on July 9.

The fighter could face a two-year suspension under the UFC’s drug program and the United States Anti-Doping Agency, which performed the test on June 16.