LAS VEGAS » Nevada regulators are considering sanctions against an Ultimate Fighting Championship star accused of avoiding an official who showed up unannounced at his gym to collect a sample to test for banned substances.

Nevada Athletic Commission Chairman Francisco Aguilar said Wednesday the panel could act next month on a complaint against Wanderlei Silva.

The Las Vegas Review-Journal reports that attorney Ross Goodman, representing Silva, conceded during a Tuesday commission hearing that Silva left the building through a back door and should have submitted to the drug test.

The commission also issued a temporary suspension for 37-year-old UFC light heavyweight Chael Sonnen who retired after testing positive for banned substances in a random test last month.

Silva and Sonnen had been scheduled to fight July 5 at the Mandalay Bay resort.