Pretty sure Lazio is keen on selling him, even within Italy. If they can get >90m for him, then it's a once in a generation chance to make profit for them. A possible game changer. And you never know what would happen if they keep him, he could get injured and lose value or he could have a bad season like Belotti had and lose 40%-50% of his value, not a risk Lazio is likely to take if someone makes a giant offer to them.
Question is do we really want to (or even can) spend more money than we spend on Higuain (which is probably necessary to get a deal) for SMS and is he really worth it!? I'm not sure about it.