14 Biggest Premier League Transfer Mistakes Of Summer So Far

12. Thomas Vermaelen - Arsenal To Barcelona

Thomas Vermaelen was touted as one of Manchester United's main transfer targets this summer but left Red Devils fans disappointed this week when he instead opted for a move to Barcelona. On the face of it, you might not consider this a bad move at all - after all, Barca are one of Europe's most successful club teams any play in front of record crowds every week. However, he would surely have been better off moving to Old Trafford. At United, the Belgian centre-back would have walked straight into a team crying out for defensive reinforcements following the departures of Rio Ferdinand and captain Nemanja Vidic. Instead, he is going to the Nou Camp where there are no guarantees of first-team football. The Catalan club have just signed Jeremy Mathieu, who appears first choice for the left-sided centre-back role, while Vermaelen will also have to compete with the likes of Javier Mascherano and Marc Bartra for the right to play at the heart of Barca's defence. The defender spend a lot of time warming Arsenal's bench last season and could find himself playing a similar role in 2014-15.