The positive test was today confirmed to MMAFrenzy.com by Nevada State Athletic Commission Executive Director Keith Kizer.
Both methadone and oxymorphone are commonly prescribed pain killers for moderate to severe pain.
The banned substances, which are considered “Drugs of Abuse” by the NSAC, were detected on a urinalysis drug test conducted by the NSAC following the bout.
Irvin has up to 20 days to request a formal hearing and faces up to a $20,000 fine and suspension.
The NSAC previously announced that all eleven fighters that were tested following the event had tested negative for steroids.