Chelski can buy anyone they want, the only problem is they will have to sell someone, because that many top players don't want to warm the bench.
For example, their general line-up is: Cech, Gallas, Carvalho, Terry, Gallas, Makelele, Essien, Lampard, J Cole, Duff/Robben, Drogba. That leaves Duff/Robben (if fit) on the bench/in the reserves along with players like Bridge, Ferreira, Geremi, SWP, Crespo and Gudjohnsen. If Chelski were to buy Deco, who would make way seeing as Lampard is also an attacking mid? With that being the case, I wouldn't mind seeing Chelski buy him. If Geremi was to be sold, I'm sure Man U would like him (unless Ballack decides on Man U).