Southampton approach for Koulibaly?

Southampton have reportedly made a formal approach to sign Napoli defender Kalidou Koulibaly.

The 24-year-old joined the Naples outfit from Belgian side Genk in 201, but has since then struggled to settle in Italy.

Koulibaly is thought to have made his mind up for a fresh challenge this summer, and Sky Italia claims that Napoli are ready to hold talks with Ronald Koeman's side over the player's sale.

The former France Under-20 international made just 14 appearances in all competitions for his club last term.