London: Chelsea have had a £50 million bid for Napoli striker Gonzalo Higuain rejected as Jose Mourinho tries to add some much-needed firepower to his attack. Napoli have not given any encouragement to Chelsea in their efforts to land Higuain and insist the Argentine, who played under Mourinho at Real Madrid, is not for sale.

Higuain has scored nine goals in 16 Serie A games since moving from Spain to Italy in the summer. That may not deter Chelsea owner Roman Abramovich, who agrees the lack of goals from strikers is the major weakness in the side. He is willing to back Mourinho in the transfer market, even though the club posted losses of almost £50 million last season.

With German club Wolfsburg keen to sign Kevin De Bruyne, Chelsea hope to receive as much as £25 million for the Belgium international who has rarely played this season. That will help Chelsea finance the move for a forward, with other sales likely this month to help balance the books. Juan Mata has been told by Mourinho that he still has a future at the club but cannot be guaranteed a starting position.

A bid of more than £20 million would be a tempting offer for Chelsea to part with him, particularly as Mata knows he needs to be playing regularly to keep his place in the Spain side. Should Chelsea sign a centre-forward this January, Demba Ba has been told he will be allowed to leave Stamford Bridge.

Ba thought he was going to Arsenal on loan in the summer, but Chelsea cancelled the proposed transfer on deadline day when Arsene Wenger landed Mesut Ozil from Real Madrid as they feared the threat of a resurgent London rival. Ba is extremely frustrated about a lack of first-team opportunities and is likely to attract interest from former club Newcastle United, as well as West Ham and Fulham, should Chelsea give the green light to his departure. The Senegal striker moved to Stamford Bridge only 12 months ago, but he has struggled to persuade Mourinho he is good enough to play regularly for a team looking to mount a title challenge. The 28-year-old has enjoyed prolific spells at West Ham and Newcastle since arriving in English football in January 2011 and Chelsea would hope to at least recoup the £7.5 million they paid for him a year ago to activate a release clause in his contract at St James’ Park.

Ba has scored just three times in 23 league appearances for Chelsea and is at the stage of his career where he does not merely want to sit on the bench, particularly as he was first choice at West Ham and Newcastle. Chelsea would be reluctant to let Ba move to a team challenging them for the title, although Arsenal retain an interest in him and are likely to bid if it becomes clear the player is allowed to move this month.