The Argentina international was linked with a move away from Old Trafford last winter. Napoli manager Antonio Conte personally spoke with him.
However, a transfer did not materialise in the end. Napoli were prepared to pay around £50m which was less than United's £65m asking price.
This has not ended the speculation over Garnacho's future and Ornstein reports that it is 'highly possible' that he could leave in the summer.
Napoli continue to remain huge admirers of the attacker and they could make a renewed approach under the recommendation of their manager.
The Naples outfit could face competition from the likes of Inter Milan and Juventus, who are also monitoring Garnacho's situation very closely.
Chelsea are also candidates to land the former Atletico Madrid graduate, but United could be reluctant to sell Garnacho to a direct league rival.