5. Frank Mir
Frank Mir is a former multi-time UFC heavyweight champion, and one of the greatest submission artists in the history of the heavyweight division. After winning two straight bouts by stoppage throughout 2015, Mir was on his way back towards the top of the division, although a decision loss to Andrei Arlovski and a recent knockout loss to Mark Hunt set him back a bit.
On top of those two losses, Mir was recently notified by USADA that his fight day sample surrounding his fight with Hunt had tested positive for oral turinabol metabolites. The former heavyweight champion denied taking any performance-enhancing-drugs in the aftermath of the news.
Recently, Mir said that the appeal process was too expensive and that he would likely be taking his suspension. He also asked for his UFC release which could prove to be a somewhat upsetting end to a legendary career due to a failed drug test.