The Lyoto Machida-Dan Henderson rematch scheduled for Saturday's UFC on FOX 19 card in Tampa is off.
The UFC announced the changeon Wednesday after Machida, the former UFC light heavyweight champion, declared the usage of a banned substance during an out-of-competition drug test administered by USADA last week.
According to the press release, Machida said he was unaware the substance, which has not been revealed, was prohibited both in and out of competition.
"The UFC organization was made aware today by the U.S. Anti-Doping Agency (USADA), the independent administrator of the UFC Anti-Doping Policy, that Lyoto Machida declared the usage of a banned substance during an out-of-competition sample collection last week," the UFC stated.