For Napoli fans hoping for upgrades to the defense, this news is pretty unfortunate: Premier League side Everton have reportedly lodged a bid for Kalidou Koulibaly.

Uh oh.

A bid submitted obviously isn't a guarantee that a player leaves -- especially since we don't know what Napoli have done with it yet, or even how large it was. That said, it's certainly not a great sign for Koulibaly's long-term future if decent Premier League teams like Everton and Southampton -- also loosely linked to the defender in the last few days -- are already sniffing around him.

Make no mistake -- while Kalidou Koulibaly had his struggles at times down the stretch last season, especially after Rafa Benitez benched him for no apparent reason, he is Napoli's most important defender. He routinely bossed games single-handedly on the back line, and took a number of very good strikers completely out of matches. His potential is still quite high compared to what we've seen, and losing him would be a huge blow to a defensive unit that cannot afford such a loss.

That said, it does make sense that if anyone would want Koulibaly, it'd be Everton -- right now, they only have two senior center backs in their squad, and Chelsea are on a relentless quest to sign one of them, English up-and-coming star John Stones. They desperately need to add depth and quality at the back, and Koulibaly is definitely the kind of player that their manager, Roberto Martinez, quite likes and would want to add to his team.

You would imagine that, under the circumstances and with Everton holding quite a lot of cash thanks to England's ridiculous TV deals, they could wrest a healthy fee from the Blues. If they can get a hefty profit on last summer's purchase of Koulibaly and flip it into two more good defenders, it could be a defensible deal to make -- but the preference would easily me to not sell Koulibaly and use other money to bring in another defender.

Please don't make this deal, Napoli. Don't take our Kalidou away from us. You need him, the fans need him, the world needs him. Make the right decision.