I don't understand the theory that set-pieces aren't being worked on though. He's said they are being worked on.
There comes a point where we say - right, whatever they are doing isn't working, or it's the players.
My opinion is that it's a bit of both. Whatever the system (not even whether it's zonal or man, but more the organisation) from Silva isn't working, but also the players simply aren't up to scratch (Zouma is perfect evidence of this - the bloke doesn't know where anyone is and NONE of our players attack the ball - which we know isn't the instruction as Silva has publicly asked them to be more aggressive).