#4 Andre Schurrle
Andre Schurrle's eye-catching performances for Bayer Leverkusen convinced Chelsea to splash £18 million on the young German. However, fate had worse things for him in store at the Stamford Bridge.
Looking at Schurrle's performances tells you he wasn't a complete failure, albeit he certainly could have done better with frequent playing chances. To start with, he had to compete with the likes of Oscar, Juan Mata, Eden Hazard, Willian and Kevin De Bruyne for a starting berth at Chelsea.
Schurrle, however, failed to gain Jose Mourinho's trust ahead of the likes of the aforementioned stars and left for Wolfsburg in 2015. Currently aged 27, he is a benchwarmer at Borussia Dortmund in Germany, and a lack of playing time has also seen him miss out on regular playing opportunities for the national team.