UFC fighter Nick Diaz’s trainer Cesar Gracie called Wednesday for the organization to overturn Anderson Silva’s victory at UFC 183 on Saturday after the legendary mixed martial artist tested positive for steroid use. Silva won by unanimous decision at MGM Grand Garden Arena in Las Vegas.

“I get it. Silva is getting up there in age but if you need steroids to fight you shouldn’t be fighting,” Gracie told TMZ Sports. “[The failed drug test] definitely tarnishes his legacy because people are going to look at his other fights and question if he was using steroids then too.”

Silva tested positive for anabolic steroids drostanolone and androstane in a random drug tested the Nevada State Athletic Commission conducted Jan. 9, Yahoo Sports reports. Officials did not receive the test results until Tuesday, days after Silva’s victory. NSAC Chairman Francisco Aguilar said the commission would have canceled the fight if it had known about the steroid use. The results from Silva’s post-fight drug screening have yet to be revealed.

“On Feb. 3, 2015, the UFC organization was notified by the NSAC that Anderson Silva tested positive for drostanolone metabolites on his Jan. 9 out of competition drug test. UFC’s understanding is that further testing will be conducted by the commission to confirm these preliminary results,” the UFC said in a statement.

Diaz tested positive for marijuana metabolites in his post-fight drug test. His exact results were not published, but the levels exceeded the UFC’s limit of 150 ng/ML, ESPN reports. Gracie dismissed Diaz’s failed test, arguing marijuana use does not affect his ability to fight.

“Anyone with half a brain would know weed is not a performance-enhancing drug,” Gracie said. “They make them take a best before they even license him to fight in Nevada.”

Both Silva and Diaz face fines and suspensions for their failed drug tests. Diaz failed tests for marijuana on two previous occasions and was suspended for a year in 2012 for drug use. The NSAC is expected to rule on the cases on Feb. 17, and will also determine whether the fight’s outcome will be changed to a no-contest.

The match against Diaz was Silva’s first fight since he broke his leg in a Dec. 28, 2013 UFC Middleweight Championship match against Chris Weidman. The 39-year-old met with a psychologist to overcome the memory of his injury, Fox Sports reported in September. Silva, who possesses a 34-6 professional record as a mixed martial artist, had never before failed a drug test.