1. Andrei Kanchelskis
The flying Russian had just enjoyed his best season for United when he was sold to Everton in 1995. Unfortunately, a mysterious falling out with Fergie – one that has never been adequately explained – was enough to convince the United manager that the skilful winger was a disruptive influence. Although only 26 when sold, Kanchelskis’ career was effectively over as his largely peripatetic career thereafter - shortlived spells at Everton, Fiorentina Glasgow Rangers, erm Al-Hilal in Saudi Arabia - demonstrated.