Chael Sonnen may not waive his right to a hearing before the Nevada State Athletic Commission and will be required to appear at the regulatory body’s next meeting to answer for his UFC 175 drug failures, according to Nevada’s deputy attorney general.

“Mr. Sonnen must personally appear and testify under oath at the commission’s July 23 disciplinary hearing,” wrote Nevada Deputy Attorney General Chris Eccles in an email to MMAjunkie. “He is expected to answer questions about the prohibited substances detected in his system as a result of the out-of-competition tests performed on May 24 and June 5.”

Sonnen’s recent response to a disciplinary complaint filed by the NSAC indicated he didn’t necessarily plan to attend the July 23 meeting at the commission’s Las Vegas headquarters. The now-retired fighter said he waived his right to a hearing, would “comply” in the “prompt resolution of this matter,” and volunteered to appear with legal counsel at a future hearing in order to “receive any discipline that the Commission deems necessary and appropriate,” but didn’t explicitly say he would appear at the July 23 session.

But according to the commission rep, Sonnen’s presence isn’t optional. The 37-year-old fighter, whom the NSAC temporarily suspended, faces up to a $250,000 fine, a formal suspension, costs related to his case, and the requirement he provide a clean drug test should he reapply for a license to fight in Nevada.

Sonnen tested positive for anastrozole, clomiphene, human chorionic gonadotropin (hCG), human growth hormone (HGH) and recombinant human erythropoietin (EPO) prior to his scheduled fight at UFC 175 opposite Vitor Belfort. Following the first positive test, which was part of a random NSAC test on May 24, he retired from active competition. The second positive test, which resulted from a June 5 test in his native Portland, Ore., prompted the termination of his employment contract with UFC broadcast partner FOX Sports.

The fighter said he didn’t dispute any of the NSAC’s findings against him but asked the commission to consider his cooperation in the case as well as the fact that he “did not compete while on the banned substances.”

Sonnen was originally scheduled to face Wanderlei Silva at the July 5 pay-per-view event, but Silva was scratched after he evaded a random test ordered by the NSAC. Belfort then filled in before the bout was ultimately scrapped completely following Sonnen’s suspension.

In Nevada, Sonnen (28-14-1 MMA, 7-6 UFC) was twice the recipient of a therapeutic-use exemption for testosterone-replacement therapy (TRT) and was even asked to advise the commission on the process before the controversial treatment was banned earlier this year. The fighter said his first positive test, which flagged him for anastrozole and clomiphene, was the result of another treatment to ween him off TRT and also to aid his fertility.

Next month, Sonnen competes in a grappling match against MMA competitor and jiu-jitsu specialist Andre Galvao at Metamoris 4 in Los Angeles.

For more on the UFC’s upcoming schedule, stay tuned to the UFC Rumors section of the site.