Chelsea should sign Kalidou Koulibaly if they wish to challenge for the Premier League title once again. There have been some reports in the media suggesting that Chelsea are planning for potential new signings in this transfer window, as they have been given the go ahead to acquire a few more players this month.

It will mean that Frank Lampard will be able to delve into the clubs transfer kitty and add a few players to the squad that will add some experience, and quality in the right areas of the pitch. And one name that will be high up on the shopping list of the Blues boss is that of Kouliably, who is easily regarded as one of the finest central defenders in Seria A, and around Europe.

Koulibaly has been outstanding for Napoli over the past few seasons and his performances has attracted all sorts of interest from the games biggest clubs, with the likes of Manchester United, Manchester City, Real Madrid and even Barcelona all joining Chelsea in the chase for the defenders signature.

It has been reported on many occasions that Napoli do not want to sell one of their biggest players and would rather keep him at the club well before he leaves for a club like Chelsea, that is how much they reportedly are desperate to keep him at the club.

However, recent reports on Gazzetta dello Sport claimPresident Aurelio De Laurentiis plans to overhaul the Partenopei squad with Koulibaly, Dries Mertens, Jose Callejon, Lorenzo Insigne, Allan, Elseid Hysaj and Faouzi Ghoulam also set to depart.

And the recent report also suggested that Koulibaly may actually be on the market for just £69 million in the January window, which is well below the £150 million that the Italians placed on his head during the summer transfer window.

Strong, classy and composed, the 28-year-old is rightly considered world-class and would be a major statement of intent from Lampard in his quest to get the club back challenging for more than a top four spot. If he is to sign big time players, then he should start with the signing of Koulibaly.