Kolo Toure
Toure enjoyed a great Premier League as one of the division’s top defenders. However, he missed a significant chunk of the 2010/11 season after he failed a drug test. This was unusual at the highest level of soccer compared to other sports like football or baseball (via Sky Sports).

It emerged that Toure used one of his wife’s weight loss pills without realizing that it contained banned substances. This was idiotic because he was responsible for what he put into his body. It didn’t cost him in the long term because he continued playing for Man City before a move to Liverpool.