Kalidou Koulibaly of SSC Napoli in action against Cagliari
Everton are struggling all over the pitch right now, and whilst fans are demanding a new striker arrives in January, manager Ronald Koeman may need to sort his defence out too.
Sunday's 1-0 home defeat to Burnley has heaped the pressure on Everton, who had spent heavily over the summer on players such as Jordan Pickford, Michael Keane and Gylfi Sigurdsson.
Manager Koeman finds himself under huge pressure to turn things around, but whilst fans want more goals, the Dutchman cannot be impressed with the state of his side's defending.
Kalidou Koulibaly of SSC Napoli celebrates after scoring
Ashley Williams and Phil Jagielka are both in their mid-30's, and with summer signing Keane losing some confidence, Everton may need to splash the cash on a dominant centre back to take charge of the defence.
One player who Everton targeted in 2016 was Napoli's Kalidou Koulibaly, though majority shareholder Farhad Moshiri told talkSPORT last November that the £60million asking price was simply ridiculous.
However, having forked out around £45million to land a player that Everton arguably didn't need in Gylfi Sigurdsson, Moshiri and Everton may need to re-consider and splash huge cash on a centre back to replace the ageing Jagielka and Williams for the foreseeable future.
Koulibaly fits the bill; the Senegal international, who joined Napoli from Genk in 2014, has become one of the most impressive centre backs in Europe, possessing outstanding pace, strength and aerial ability, as well as ability on the ball to step out from the back.
With a deal for Southampton's Virgil van Dijk unlikely, Koulibaly may be the next best option for Everton, and whilst Moshiri wasn't impressed with the asking price last time Everton tried to sign him, they now need him more than ever – and they should be looking to land him as Keane's centre back partner in a hugely ambitious move.