Obviously Pique. He has been so inconsistent and he is terrible at the offside trap.
Second worst buy has been Keita. He is such a useless utility man, everytime he get's the chance his work rate has been nothing short of atrocious.
Caceres has been pretty poor. Another one who, when given the chance, has failed to impress and more than often makes crucial mistakes.
Hleb....What a player, even better buy than Dani Alves.