4) Alvaro Morata (Real Madrid to Chelsea – £60m)
The Spaniard had a good reputation during spells with both Juventus and Real Madrid, but his goal return of 15 goals in his first season was not what Blues fans were expecting after the club spent a sizeable amount of money.
After making it known that he wished to leave, Morata was loaned out Atletico Madrid just 18 months after his arrival at Stamford Bridge. He moved on a permanent basis last summer.