After the UFC Fight Night 44 card in San Antonio, the UFC issued an official statement on the matter, saying it supports the commission's effort to clean up the sport.
(Update, Sunday, 7 pm ET: We're adding the UFC's full official statement below:)
"With regards to Chael Sonnen, we were made aware that a second random test conducted earlier this month resulted in a positive test for additional banned substances.
Chael will have the opportunity to appear in front of the Nevada Athletic Commission next month, and through a statement released to media tonight, he's pledged his cooperation.
Our stance on the subject remains the same. We support the commission and will continue to work to ensure that all UFC competitors compete free of performance-enhancing drugs and banned substances."
Sonnen, who had originally failed a May 25 test, the results of which were announced on June 10, also took a blood and urine test at NAC's request on June 5. It showed human growth hormone, recombinant human erythropoietin, anastrolzole, and human chorionic gonadotrophin in his system.
Sonnen is an analyst for the UFC's broadcasts on FOX Sports 1. FS1 made no mention of the Sonnen news during the evening's UFC Fight Night 44 broadcast.