Chelsea boss Carlo Ancelotti has an extensive list of defensive transfer targets for this month's market.
Benfica defender David Luiz remains his priority, though Chelsea refuse to meet the Lisbon club's £26 million asking price.
Ancelotti has drawn up a shortlist of five possible centre halves which is also understood to include Wolfsburg's Simon Kjaer, Bolton's Gary Cahill and Lazio's Stefan Radu.
Manchester City stopper Joleon Lescott is also under consideration.
Kjaer, 21, only moved to Wolfsburg last July for £11m but has had a difficult season.
