Chelsea will monitor Alex's recovery from a knee injury before deciding whether to pursue their interest in a replacement centre-half next month, with Carlo Ancelotti expected to target a young English replacement such as Gary Cahill or Steven Taylor if he deems reinforcements to be required.

Alex underwent surgery to flush out the joint this month and is not expected to be fit enough to return to the first team until the end of January at the earliest. Any setbacks in his rehabilitation will drive the champions into the market, with Roman Abramovich having indicated that funds will be available for Ancelotti to strengthen, albeit only at the centre of his defence, despite his adopted policy of leaning on the club's academy graduates. The manager is satisfied with that situation.

"We have a big question mark over Alex, one of our injured players, and his injured knee," said the Italian. "We hope that he will have resolved his problem by 31 January and, if that is the case, we won't need another defender. But we have to wait and see his condition. We can think about things – a new defender – towards the end of January. That would be the only position [we would look to strengthen]."

Asked whether the pursuit of an Englishman, and therefore a player classified as homegrown to fulfil the Premier League's 25-man squad criteria and used to the rigours of the domestic top flight in this country, Ancelotti replied: "Obviously, if you take an English player, you don't have a problem with the culture, the language. Maybe they have advantages for this reason."

Bolton Wanderers have indicated they will resist attempts to prise Cahill, an England international, from the Reebok, with Alan Pardew hoping to retain Taylor's services at Newcastle United despite protracted talks over a new contract, with his current deal to expire in the summer. Those clubs' resolve may now be tested as Chelsea's longstanding defensive target, the Benfica centre-half David Luiz, is currently valued by the Portuguese club at nearer £40m, which would price the champions out of the pursuit of his signature.

Regardless, Ancelotti believes his side will welcome back their key performer at the Emirates tonight when Frank Lampard makes his first start since late August, with the manager insistent that the midfielder is irreplaceable in the market. The 32-year-old is now fully recovered from groin and hamstring tendon complaints and ready to make an impact as Chelsea seek to end a dismal recent run that has yielded a solitary win in seven Premier League matches.

"In the market there is no player capable of replacing Lampard," said Ancelotti, whose side have managed only four goals in those seven matches. "Every player has different skills. John Mikel Obi is not able to score but is fantastic defensively. Ramires the same. Michael Essien has, I think, his skill to score from outside the box but he was injured for a month, so his condition has not been so good. He has used this time to improve, so maybe Essien can support the team up front. But I am happy to have Lampard back.

"It will be important to have his support in our attacking play, and when we have the ball. That will increase our possibility to score. It's very difficult to find this kind of player who has the capability of scoring 20 goals from midfield. He has character, ability, he always runs and works hard, not speaking. He's so professional. It's the best image for a player. I don't like players who speak but don't run. I like players who don't speak but run. They do their talking on the pitch.

"Having him back will be fantastic news for the next game. He will be able to play. He's fit. He's excited. For us, he'll be very important. I don't expect anything extraordinary from him. Just what he's able to do. He has a special ability and he's always retained that. He doesn't miss that now. His problem is resolved and he won't have any more trouble with it. In fact, of all our players, he is the one in the best condition at this moment."