All this feels like bullshit to me. A CB like Santacroce being sold for €5-6m? It's too good to be true. Also I doubt he's not in their transfer plans since every single club needs atleast 2 CBs, its not like he's a midfielder or something. He also had a good season, so all the transfer rumours circulating around him seems very suspicious.
You may question the price, but there is something to them putting him on the market, Marino said they will listen to good offers from us, Donadoni doesnt seem like to be a fan, some of his discpline and drink and driving may be troublesome, AND most importantly, they are afraid he might lose his value if he is on the bench alot next season, because they bought a rightsided CB who plays exactly in his position, Campagnaro, and he will for sure start alot prolly.
Regarding the price, if it was before last season, they could demand alot, but based on last seasons sketchy season, they can hardly demand much, they cant for any Napoli player, non of them had convincing season, Santacroce in particular had troublesome season.