Manchester City have reportedly joined the hunt for Napoli defender Kalidou Koulibaly.
Long-serving captain Vincent Kompany left the club during the summer, meanwhile, meaning that Fernandinho has had to be pressed into action alongside Nicolas Otamendi, who struggled in Sunday's 2-0 defeat to Wolverhampton Wanderers.
According to reports in Spain, City boss Pep Guardiola has made it clear that he wants the club to sign a new centre-back in January, and Koulibaly has been identified as a possible acquisition.
The 28-year-old, who was linked with both Manchester United and Real Madrid during the summer, has made over 200 appearances for Napoli since arriving from Genk in 2014.
However, Napoli are said to be unprepared to sell the Senegal international unless his £110m release clause is activated, which could price the Citizens out of a mid-season swoop.