The Brazil international Alex is expected to end his three-year loan at PSV Eindhoven to complete his move to Chelsea, and Mourinho has also been linked with a new offer for the Bolton defender Tal Ben Haim, who is a free agent.

Mourinho hoped to sign another midfielder alongside Sidwell, with John Obi Mikel and Michael Essien likely to be playing in the African Cup of Nations in January and February.

Asked how many newcomers might be joining Sidwell, Mourinho, in Africa on a charity mission with Chelsea, said: "I think three, and it is obvious a central defender because we have problems during the season with injuries in defence. A central defender, a midfielder and a striker."

He also suggested that he wanted an improvement from some of the players who arrived last summer. "I expect more from [Michael] Ballack this season, and from [Andrei] Shevchenko, much more," he said.

Pizarro has already joined on a free transfer from Bayern Munich, and Mourinho is optimistic about the impact the Peru international can make in the Premiership. "He is a player with some qualities, we think he can be important for our group and important for the Premiership," Mourinho added.

"[Pizarro is] a player with experience of responsibilities because when you play with Bayern Munich in Germany it means you play for a top club."

Pizarro could prove invaluable if Didier Drogba is called upon by Ivory Coast for the African Cup of Nations, a competition that will lead to widespread disruption in the Premiership.

"I will try to keep them [the African players] until the last moment, just before the competition starts, but they have the Fifa rules on their side so if they want to go a couple of weeks before the competition starts just to train we have to let them come," he said.

"This is the kind of co-operation I hope we can have, and lose the players for three weeks and not five. Players should go straight to the game, not two weeks before. We have to try to reach an agreement with the nations so clubs don't suffer too much when players leave."

Fifa, the world governing body, has rules that state clubs must release players at least 14 days ahead of an international tournament.

"The players will only be training two weeks before the Nations Cup, while we will be playing crucial matches in Premiership at that time of the season," Mourinho said. "There is no need to fight the federations because they have the backing of Fifa. But if we cannot co-operate with the African federation over this problem I think I will not sign any more African players because we compound our own problems."

However, Mourinho was keen to underline that he will not prevent any of his African players from playing in the Nations Cup. "It is the pride of my African players to play for their countries and I will not prevent them. This tournament is important for the players and the people of Africa and I respect that."