Chelsea manager Jose Mourinho says his side miss the influence of Michael Essien in midfield when he is forced to play in the centre of defence to cover for injuries.
The 24-year-old Ghana international has had to play at the back to cover for injuries to John Terry and Khalid Boulahrouz, with Mourinho admitting that the Blues miss Essien's drive in midfield as a result.
Mourinho said of Essien; "You cannot imagine how much we miss him in midfield.
"He is one of the best midfield players in the world and he is not playing there. It is as simple as that.
"If I now have another problem in the centre of defence, the next one I play there is Didier Drogba. So if Ricardo or Michael has a problem, Drogba will play as a central defender and I miss him in attack.
"You always miss players when they cannot play or cannot play in their normal position.
"Michael is good in defence, but he still thinks like a midfield player. He is strong, quick, and good in the air and can tackle.
"So he has qualities to play in defence, but in many ways he still thinks as a midfield player."