#2 Radamel Falcao
When Radamel Falcao moved to Monaco in 2013, he was one of the best players on the planet, even being named in the FIFPro World XI in 2012.
His move to France started well but an ACL injury he suffered midway through his debut season ended his World Cup hopes and that destroyed his morale severely.
Falcao signed for Manchester United on deadline day in the summer of 2014 on a loan deal and there was a lot of expectations due to his reputation. However, he was nowhere near his best following the knee injury and ended the season with four goals in 29 games of which only 17 were starts.
The following season he returned to England to play for Chelsea and this proved to be an even bigger disaster as he made two starts, played 10 games in total, and scored just one goal in the entire season.