Former Chelsea star Frank Leboeuf has admitted he’s as surprised as anyone at how bad Kalidou Koulibaly has been since joining the club from Napoli.

Leboeuf told Si & Dan Talk Chelsea: “I’m as stunned as everyone else. I was so happy when he signed. I said ‘yes, that’s the player we need – strong, leader at the back for Napoli, great player, great mentality, alongside Thiago Silva, wow, that’s going to be fantastic.

“I think Kalidou Koulibaly will be the first one to admit his disappointment. We are all disappointed, because he hasn’t yet fulfilled any expectations. The fact that behind him though, the goalkeepers do not provide too much security with their form lately, doesn’t help.

“But still, I really thought that Chelsea had one of the best central defences this summer with Wesley Fofana, Silva, Trevoh Chalobah, and Koulibaly. But it’s not what’s happened and I’m sad about that.

“Sometimes it takes time to settle in. It was easy for me, I can’t explain why, but I felt so good so early during my time at Chelsea. But sometimes it takes longer for some players to settle down, and if Chelsea have time and try to organise everything, and maybe Kalidou next season is going to be fantastic and show the world that he is still the player Chelsea signed from Napoli.

“I have doubts though and we are all disappointed. I want to believe it’s not the end of it, you don’t lose all your tools like that, it’s impossible. It’s just mentally that he has to fix some stuff, maybe with his family. I think we have to give him a chance to show the world that he’s still a good player.”