The 33-year old former Strikeforce lightweight champion tested positive for what was termed "exogenous origin of testosterone metabolites" following his UFC 188 loss to Eddie Alvarez.
As a result, Melendez has been suspended for one year and has been pulled from his scheduled July 15 bout against Al Iaquinta in San Diego. The UFC announced it is seeking a replacement opponent for Iaquinta.
"Regrettably, I tested positive in my post fight urine sample for UFC 188," Melendez stated. "I did not inject anything, but I am responsible and accept the consequences for the results.