I don't think he will leave, but IF he does leave, then contrary to popular belief I don't think we will miss his 30 goals per season like some may think.
I reckon that we will probably score just as many goals without him. His goals will be spread evenly among our forward line.
We scored 86 goals in the 2017/18 Serie A season, and we haven't come close to that since he joined us.
Of course I could be completely wrong, but that's my gut feeling.