Chelsea have developed as the rumoured favourites to sign centre-half Kalidou Koulibaly from Napoli once the transfer window reopens.

The West Londoners missed out on the 26-year-old last summer and have since seen rival sides reportedly join the hunt to secure his signature.

Premier League foes Arsenal and La Liga side Barcelona are believed to be in the mix to land Koulibaly, who has made part of the second-best defensive system in the top Italian league this season.

As reported by the BetStars, but, it is Chelsea who now leads the way to nab the in-demand Senegal international, as they seek a replacement for the rejected David Luiz and ageing teammate Gary Cahill.

The defender, under contract with Napoli until 2021, has also earlier been touted as a potential target for Manchester United.

Meanwhile, Serie A giants Inter Milan have reportedly told Chelsea and Barcelona that Yann Karamoh is not for trade.

Both sides have been linked with moves for the teenager in last days.

The 19-year-old has impressed at the San Siro following his summer move from Caen on a two-year loan deal.

As reported by Corriere Dello Sport, Inter have reacted to interest from Chelsea and Barcelona by telling them to back off.

Karamoh, who was reportedly watched by the two admirers in January, is expected to be signed up by Inter when the loan comes to an end as the Serie A giants have an option to buy.