#10. Radamel Falcao
He was once the most lethal forward on the planet but Radamel Falcao’s career went on an almighty nosedive. Go back to his time at Atletico Madrid and Falcao was amongst the best players on the planet. He scored 70 goals in just 91 matches for the club during two seasons, helping the club to victory in the Copa del Rey and the Europa League. So it was surprising when he transferred, not to one of the bigger European clubs, but to the newly-promoted Ligue 1 side Monaco. In January 2014, Falcao suffered an injury to the anterior cruciate ligament in his knee, effectively ending his season and ruling him out of the 2014 World Cup in Brazil. Falcao never really recovered from that and looked a shadow of his former self during spells at Manchester United and Chelsea.