16) Mats Hummels (Borussia Dortmund)
One of the best defenders in the world, a host of top clubs are supposedly chasing Borussia Dortmund and Germany centre-back Mats Hummels this summer. Arsenal and Manchester United are linked as his main suitors in England, while Barcelona and Juventus are also known to be tracking him as he surely looks set to make the move to a bigger club sooner or later.