Chelsea are in the market to bolster their defence following the exits of Antonio Rudiger and Andreas Christensen.Thomas Tuchels side have already added Kalidou Koulibaly from Napoli for 35million.The Blues are eager to add another centre-back to their ranks before the closure of the transfer window.TOP STORY BLUES TO MAKE WORLD-RECORD BID FOR FOFANA Chelsea are preparing to make a world-record...