Warning for Ross Barkley: Seven youngsters signed and never used by Chelsea, including Premier League goal machine

2) Romelu Lukaku (Everton)

Signed as a highly promising teenager by Chelsea, Romelu Lukaku scarcely got a look-in for the first-team, despite clearly impressing on loan at West Bromwich Albion and then Everton, whom he was allowed to join permanently. The Belgian has clearly been a top talent for some time but for some reason ignored by the Blues.