Former UFC light heavyweight champion Lyoto Machida as admitted to taking a banned substance and his scheduled bout with Dan Henderson is now off. According to a statement released by the UFC, Machida was not aware that the substance was on the banned list for both in and out of competition testing.

“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. Machida stated that he was unaware that the substance was prohibited both in and out of competition and, in accordance with the UFC Anti-Doping Policy, his disclosure of usage will be taken into consideration by USADA during any potential results management and adjudication process.

Given this information, UFC officials have elected to remove Machida from his scheduled bout against Dan Henderson this Saturday in Tampa, Fla. Henderson will be re-booked for a new bout in the near future.”

Henderson and Machida were set to square off on this weekend’s UFC on Fox event. It would have been a rematch between the two fighters. They originally faced each other in 2013 at UFC 157. Machida would take home a split decision victory.

Neither Machida nor his representatives have yet to officially comment on the situation but his former opponent took to Twitter to express his frustrations.

According to UFC officials, Henderson will be moved to a later event with a new opponent.