[sorry I don't write good english]
Gabbiadini is a fantastic, fantastic player with tremendous upside, his natural role is second striker.
Sarri, Napoli FC coach, never change team schema.
Napoli play 4-3-3
2 winger in very very large position, with pace, dribbling and cross ability, one powerful center forward with great strike ability, a finisher (like Higuain).
Before Gabbiadini Higuain reserve was Duvan Zapata (6 ft 1 in).
Gabbiadini main abilities are shot, first touch, give & go, motor, he don't fit Sarri soccer vision.
Gabbiadini lost confidence and then stop fight for position.