United, willing to make Koulibaly the most expensive centre-back in the world

Manchester United's defence is struggling. Harry Maguire's recent injury - despite not being anything serious - and Eric Bailly's, Axel Tuanzebe's and Marcos Rojo's performances have forced United to strengthen the area. 

That's where Kalidou Koulibaly comes in. The Napoli player is on Machester United's wish list, but his departure could be difficult to negotiate. The Senegalese has a very good relationship with Napoli president Aurelio Di Laurentiis, who could block his exit. 

But according to the Daily Star, Manchester United are prepared to pay as much as 100 million euros for his signing, as they believe the former Genk player fits perfectly into the team. 

If the transfer did go through, Koulibaly would become the most expensive centre-back in the world, just above his possible future teammate Harry Maguire.