Chelsea have launched a bid for Napoli defender Kalidou Koulibaly.

La Gazzetta dello Sport says Chelsea have already tabled contract terms to Koulibaly.

They have offered the 30-year-old personal terms worth £8.5m-a-year.

That works out at just over £160k-a-week.

Napoli though are claimed to be demanding £34m for their star centre-back.

But the Serie A outfit could be forced into a sale this summer with just 12 months left to run on Koulibaly's current contract.

Barcelona are also understood to be interested in a swoop for the Senegalese international.