Chelsea manager Andre Villas-Boas is planning to sign another player in the January transfer window in addition to the signing of Bolton Wanderers defender Gary Cahill.
Cahill is close to competing personal terms ahead of a move to Stamford Bridge.
And Villas-Boas is hoping to add further to his Champions League chasing squad with another signing later in the window.
"Apart from the central defender we might get one more player in, but we're not sure yet.
"It's always difficult (in January). First of all, the top talent is normally cup-tied in the Champions League, or in the different domestic competitions.
"It's difficult for the selling club to make players available. So it's normal to struggle in the transfer market.
"Normally it's a market where you overpay a lot and that's not what we want to do now. I think that's why we've set out not to do a lot in the transfer window."
While bringing in players is a priority, Villas-Boas says letting players go out on temporary loan deals is not a target for The Blues.
"We don't have a lot of players that we are going to send out on loan," he added.
"Those conversations were made at the beginning of the season and eventually we went on from that. There were conversations regarding one or two players that went the other way."