Petr Cech admits it's the defence as much as the attack that are letting down Chelsea this season.
Carvalho has missed the last five games - of which Chelsea have won just one - because of injury and will miss the trip to Manchester United on Sunday too.
Cech said: "We have not been up to standard and have to do something about it. We have conceded too many from set-plays and that just wasn't the case last season."