Thiago Silva
Thiago Silva has constantly flirted with becoming a serious light heavyweight contender in recent years, but losses to Lyoto Machida, Rashad Evans and injury woes have held him back from getting a shot at a title.
After recurring back injuries in 2010, Silva attempted to use banned substances in order to remain healthy for his fight with Brandon Vera at UFC 125. In an effort to mask these substances from the athletic commission, Silva cheated on his pre-fight drug test, for which he will now serve a one-year suspension.
By the time Silva returns from suspension, he will have wasted the last two years of his career. Even if Silva does come back healthy for once, he will have to earn the UFC's trust and run through a light heavyweight gauntlet before he can even get a shot at the title.