Kalidou Koulibaly is one of the best defenders in Europe at the moment and has recently become unsettled at Napoli. The Italian side currently sit seventh in Serie A, 17 points behind leaders Inter Milan. Chelsea fans are desperate for Koulibaly to join the Blues, but here is why Chelsea should not sign Koulibaly.
The Chelsea defense has looked uncertain of late and has come in for criticism. It is screaming out for an experienced head to organize the back-line and stop the Blues conceding so many goals this season.

Koulibaly is certainly this. The Senegalese defender has made almost 200 appearances for Napoli and 38 times for his national side. However, he is now 28-years-old. Although this is not an immediate issue, the price tag he would demand makes this an important factor.
The Daily Mail has reported that Premier League rivals Tottenham Hotspur are considering a £90m bid. That would be a major investment for any player, but it is an astronomical amount for a man approaching his 30’s.

There is also the possibility that Koulibaly does not adapt quickly to the Premier League. Unlike other potential center-back target Milan Skriniar, the Napoli man does not have time on his side. If it took him a season or two to adapt, he would be verging on 30 and could begin to decline.
This is, of course, an uncertainty. Center-backs traditionally find it easier to adapt than attackers. If Koulibaly were to make a ‘Van-Dijk like’ impact at Stamford Bridge, then his age and price tag will quickly be forgotten.