#4 Kalidou Koulibaly (Napoli)
Kalidou Koulibaly is one of the best defenders in world football right now. The Senegalese international plays for Napoli in Serie A. His defensive exploits have made him a rock at the back for the Italian outfit as he continues to draw interest from top clubs across Europe.
He is 6'4 inches tall, strong, quick and he has a great ability on the ball as well. Due to his style of play, the Napoli fans call him The Wall. Since John Terry's departure, Chelsea don't have a player who has a commanding presence at the back and Kouibadly could just be the answer to that.
Chelsea have been linked many times with a move for the former Genk defender many times. But they will have to battle it out with Manchester United who have been linked with a move for him.
Though the Napoli defender has asserted that he happy to stay in Naples but the chance to challenge for titles every season with a team like Chelsea would surely tempt him. So, far it seems like Napoli are way behind challenging Juventus for Serie A and Koulibaly as a result of which would want to leave the San Paolo.