More to the point, where does Essien fit in?
It's the same at Man United where they have Hargreaves, Carrick, Fletcher, Scholes etc. Chelsea are building a squad for an assault on all 4 competitions. Letting Lampard leave purely because they've brought one player in just doesn't make sense. Makelele will be going I think, so can they really afford to sell him?
What do you envisage the midfield 3 being like (assuming no more transfers and that Scolari will stick with 4-3-3)?
I'd have thought:
-----------Essien------------
---Ballack----------Deco----