Former heavyweight champion Frank Mir announced Saturday that he has been granted his release from UFC.

Mir was in the midst of serving a two-year suspension for testing positive for a banned substance in April. He has denied any wrongdoing since receiving news of the failed test.

"I have consistently denied knowingly taking anything that would violate USADA's guidelines," he wrote on his Facebook account.

"As hard as it was to try to retrospectively analyze everything I had consumed within a fairly recent six week period of my life," he added, "I would have no idea where to start going back years into my past."

Mir last appeared in a UFC match in March 2016, which resulted in a knockout loss at the hands of Mark Hunt. It was the fifth loss in the last seven matches for the 38-year-old fighter.

Although he has struggled as of late, Mir was once one of the biggest stars in the sport. He won the belt for the first time in 2004 with a win over Tim Sylvia and won it again in 2008 after beating Minotauro Nogueira. Unfortunately, he lost in his first title defense each time.

He has an 18-11 record in his MMA career, with all but two of those bouts coming in UFC.