Anderson Silva tested positive for methyltestosterone (a synthetic testosterone) and a diuretic when he failed a test carried out by USADA in November of last year, the second test failure of his career. It puts a return to the cage in serious doubt.

Silva first failed a test for banned substances in January, 2015 — something he claimed was the result of a contaminated sexual aid. With this being his second failure, Silva faces a far longer period of suspension of up to four years. Combine that with the multiple substances found in his body, and he could face a further four (for a maximum of eight). The news comes from a report by Combate.

Silva’s representation is believed to be arguing that his first failure from 2015 shouldn’t be brought into the decision making process, as it came before the UFC introduced USADA and a year round testing system. USADA’s position is that test failures prior to their UFC partnership can be taken in to consideration, and so long as failures take place within ten years of each other, they will be considered multiple violations.

According to the report, at 42-years of age, Silva will likely retire should USADA hand down a suspension of two years or longer.

For what it’s worth, Silva still maintains his innocence. Recently speaking to TMZ on the street, Silva stated he had “never in my life” used steroids, and that he was “excited” for his upcoming hearing. Should he be found guilty, it would be a sad end to one of the greatest careers in mixed martial arts’ history. At one point in time, Silva was regularly pointed to as the greatest of all time, and his run as middleweight champion still remains one of the best runs ever in MMA.