Chelsea manager Antonio Conte has reportedly made an official approach for Napoli defender Kalidou Koulibaly for what is expected to be a club-record move.
The Blues are looking to strengthen their central-defensive ranks this summer and are said to have earmarked the 25-year-old as their top target.
According to The Telegraph, Chelsea have now made their first move in an attempt to lure Koulibaly to Stamford Bridge by making a £60m bid - £10m more than the sum spent to bring Fernando Torres to the club in 2011.
Should terms be agreed between the two teams, it is claimed that Conte may consider altering formation with a back-three - made up of John Terry, Gary Cahill and Koulibaly - much like in previous posts with Juventus and Italy.
Chelsea are also hopeful of seeing Kurt Zouma return from his long-term injury layoff before the calendar year is out, which could spell trouble for one of Terry or Cahill.
Koulibaly has previously been linked with Manchester United and Arsenal, although neither side is believed to have made an official approach for the former Metz youth player.
