Manchester United want to sign Kalidou Koulibaly.

But the Red Devils are prepared to wait until the summer if necessary, according to ESPN.

United see the 27-year-old as the man who can shore up their back line.

But they are aware that Napoli will not want to sell in the winter, even for a world record sum.

And ESPN also claims the defender is open to a move.

United have not ruled out a January signing, but the club has always maintained that doing deals is harder in the middle of the season.