La Republicca says United have been long time admirers of the centre-back who turns 29 this month and has attracted interest from an array of top European clubs.
Should he leave Naples in the summer then United are favourites to land him in a deal which could be for just £80million.
Although the fee still remains high, it comes following Napoli president Aurelio De Laurentiis having rejected offers for around £90million last year.
The lower fee now comes as a result of the coronavirus outbreak that has wreaked financial havoc to teams across Europe.
French reports also claim that European rivals including Paris-Saint Germain, Barcelona and Real Madrid have opted to focus on other targets, but United still have competition domestically, including from Liverpool.