Chelsea Transfer News: William Carvalho Battle with Everton, Latest Rumours

Chelsea are reportedly eyeing a move for Sporting Lisbon central midfielder William Carvalho but face a battle with Everton to sign the Portugal international. 

According to Darren Lewis in the Mirror, the Toffees "lead the chase" for the 24-year-old, but Chelsea have turned their interest to him after struggling in their bid to sign AS Roma's Radja Nainggolan.

Per Lewis, new Blues head coach Antonio Conte is eager to add further strength to his squad's engine room after signing N'Golo Kante from Leicester City, and £30 million-rated Carvalho is now a key target, with Sporting quoting Chelsea £50 million to sign Joao Mario.

Carvalho has proved himself over the last few seasons to be one of the best young defensive midfielders in Europe and was a key part of the Portugal side that won Euro 2016 earlier this month.

He could be the perfect partner for Kante in Conte's squad—either in a 4-4-2 or 3-5-2 formation, per Bleacher Report's Sam Tighe—particularly as Nemanja Matic was so disappointing last season for Chelsea:

Carvalho is hard-working, strong, comfortable on the ball and boasts an excellent passing range, all attributes that have likely attracted Conte and Chelsea.

At £30 million, he would also be a good-value buy in the current market, especially as he is still to reach his peak and already boasts top-level international experience.

Chelsea will not take part in any European competition next season, but Conte is clearly building a squad capable of fighting on multiple fronts in the future.

The Italian recently ruled out the possibility of selling Matic, who had been linked with Juventus, saying the Serb is "an important player" in his squad, per Sky Sports' Nick Lustig.

Should Chelsea sign Carvalho, they would boast an impressive core of central-midfield players including the Portuguese, Kante, Matic and Cesc Fabregas.

Under former manager Jose Mourinho, Fabregas and Matic were the undisputed central pairing, but that will clearly not be the case under Conte, with the Italian set to introduce a new system at Stamford Bridge.

With four such talented central midfielders, Conte would have the luxury of rotating at will, but the arrival of Carvalho could spell the end of John Obi Mikel's career at Chelsea, with the Nigerian having previously hinted he would look to move if he could not secure first-team football, as reported by Goal (h/t the Evening Standard's Simon Johnson).

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As well as the centre of midfield, Conte needs to add strength to his centre-back department, and Chelsea are also reportedly in another battle with Everton to sign Napoli's Kalidou Koulibaly.

Per Lewis, Toffees majority shareholder Farhad Moshiri has thus far matched everything the Blues have offered for the 25-year-old Senegal international, and the Merseyside club do not appear to be backing down.

Chelsea will undoubtedly remain in the fight for Koulibaly as he could add physicality and expertise to a central defence still overreliant on John Terry and Gary Cahill.