Romanian boxer tested positive for a banned substance after a draw against Badou Jack on April 30 at the DC Armory in Washington, D.C., according to North American media.
Canadian media say the information was posted by journalist with the ESPN sports channel Dan Rafael on Twitter, mentioning that Bute tested positive for the substance ostarine (also called enobosarm), which is not an anabolic steroid but is said to increase stamina and recovery ability and produce similar results that steroids would.
The WBC middleweight match between the two ended in a draw after 12 rounds, but the Gambia-born Swede Badou kept the title. Two judges scored the bout 114-114 and one had Jack winning 117-111.
The D.C. Boxing and Wrestling Commission was responsible for the testing.
Bute, 36, (32-3-1, 25 KOs) is a former IBF world champion 2007 to 2012, in which time he defended the title nine times.