Alex Rodriguez
A-Rod was one of the biggest baseball stars of his era but his career ended in disgrace. The seedy superstar took performance-enhancing drugs and cheated his way to the top of the sport. The Biogenesis scandal revealed the truth after Rodriguez denied any wrongdoing (via NPR).
In the end, the facts emerged and MLB suspended him for an incredible 211 games. However, they reduced this slightly on appeal but the damage was done. He missed a full season before he returned to action as one of the league’s polarizing figures. Baseball remains one of the dirtiest sports on the planet.