Story updated at 3:23 p.m. ET to reflect comment from UFC anti-doping partner USADA. 

Former UFC middleweight champion Anderson Silva tested positive for methyltestosterone – a synthetic testosterone – and an unspecified diuretic prior to UFC Fight Night 122, according to a recent report.

Silva’s reps are pushing for a reduced suspension following the ex-champ’s second failed test, arguing a failure from January 2015 was not under the U.S. Anti-Doping Agency and shouldn’t be considered when deciding his punishment. Silva (34-8 MMA, 17-4 UFC) failed an out-of-competition test and was pulled from a fight with Kelvin Gastelum (14-3 MMA, 9-3 UFC) at the event this past November.

USADA might factor in doping violations that occurred prior to the implementation of the UFC’s anti-doping program. Each violation must take place within the same 10-year period in order to be considered multiple violations.

Silva (34-8 MMA, 17-4 UFC), 42, faces a four-year suspension for his second positive test and may receive additional time for multiple substances found in his system. His reps say he will retire if he is ultimately suspended at least two years, according to the report today from Brazilian website Combate.

According to the report, sources close to the UFC confirmed the substances for which Silva tested positive prior to fighting Gastelum. UFC anti-doping partner USADA declined comment, citing Silva’s pending case.

Methyltestosterone, sold under the brand names Android, Metandren, and Testred, is typically used to treat men with low testosterone levels, boys with delayed puberty, or in small doses for menopause hormone therapy.

Silva, once the most dominant presence in the UFC middleweight division, first ran afoul of regulators in connection with a fight against Nick Diaz at UFC 183. Silva failed pre- and post-fight tests, coming back positive for a steroid metabolite, synthetic testosterone and anti-anxiety drugs. In a hearing, he claimed the testosterone came from an over-the-counter sexual enhancer. The Nevada State Athletic Commission, which regulated the event, was not convinced and suspended him for one year and fined him $380,000.

Shortly after his second positive was announced, Silva again denied using performance enhancers and said he would fight USADA’s findings. His coach later claimed the failure was the result of a tainted supplement. Two months ago, Silva said his team is working with USADA to discover the root of the positive test.

The drug issues have cast a shadow over Silva’s legacy in the octagon. Former UFC featherweight champion Jose Aldo said the beloved Brazilian will seriously damage his legacy if he is proven guilty in connection to the most recent failure.

Former middleweight champ Michael Bisping (30-9 MMA, 20-9 UFC) took Silva’s place at UFC Fight Night 122 and was knocked out by Gastelum (14-3 MMA, 9-3 UFC) in the first round.

For complete coverage of UFC Fight Night 122, check out the UFC Events section of the site.