Kalidou Koulibaly is going to be a name dropped in a lot of transfer rumors this season, and the wave has already begun: according to reports in England, Chelsea have already made overtures to sign the big defender, and Napoli have rejected them out of hand.
The size of Chelsea's bid is unknown, but it's not surprising that they'd chase Koulibaly. The Senegalese defender made massive strides this season under Maurizio Sarri, going from a talented but inconsistent talent to one of the most dominant defenders on the continent. With how much Chelsea need to rebuild their back line, Koulibaly with his top-shelf physicality and good technique makes perfect sense for them -- but with the Champions League calling, it would take a massive bid for Napoli to give him up.
Apparently that bid didn't come, because Chelsea are believed to be moving on to another Serie A defender, Roma's Kostas Manolas. Keeping Koulibaly and getting Chelsea to take away a top defender from a direct rival in one move would be a pretty sweet coup for Napoli to pull off this summer.
Still, this isn't going to be the last we hear of big clubs approaching Napoli for Koulibaly this summer. As one of the top young defenders around, he's going to be an attractive target for clubs wanting to improve their defense. Napoli will do everything they can to keep him, but they can bet they're going to have to fend off plenty of interest before the summer is done.