Worried about whether Edison Cavani is worth his buyout clause? Well, you should be, because acquiring him would cost Chelsea a lot of money, especially when you consider that he'd end up on superstar-level wages for five years. Heck, even Cavani himself is questioning whether the release clause is reasonable:
I don't think I'm worth €63m. I will talk to De Laurentiis about it. I owe a lot to Napoli and I want to leave through the front door if I move on.
-Source: Marca via Sky Sports.
There are a couple of comments to make at this point. First of all, Cavani agreed to the clause when he signed the contract so you can't really complain about it afterwards. Said clause is completely fair from Napoli's standpoint -- Cavani on low wages and locked into a long-term deal is worth a lot of money over the next few seasons, especially if his goals can fire the club into the Champions League again.
Second, of course Cavani thinks his buyout clause is too high. A high buyout clause means that he gets less money from whichever club he'd end up going to -- if Chelsea budget €100 million for the Cavani acquisition and €63 million goes to Napoli, that's less that can go to the player himself. It's in his best interests to avoid the club gaining the leverage of a big(ger) fee when it comes to negotiate personal terms.
So, long story short, the main motivation for Cavani saying he's worth less money is so he can make more money. I love transfer economics sometimes.