Koulibaly spoke to Algerian television station El Heddaf TV.
“I am very close to Faouzi and we share a room at training camp, so I feel a little lonely now that he's injured," confessed Koulibaly.
“Maurizio Sarri is right to say his absence has a big impact on the team. Everyone knows the contribution he brings on the left. He is also a very positive presence in the locker room and I hope he'll be back soon, because we really miss him.
“I am very happy he signed a new contract, as I was afraid he'd leave. I encouraged him to sign the extension and remain with us at Napoli, as he's very important if we are to achieve our objectives.
“At this moment, Ghoulam is the best left-back in the world. I don't say that because he's my teammate, but because it's the truth."