Smalling joined Roma on a season-long loan deal from Manchester United during the summer transfer window and has done reasonably well for the Italian club. Roma are planning to sign the 30-year-old on a permanent basis, but United are demanding a fee in the region of £25 million.
However, United are only willing to offload Smalling to Roma if they manage to sign Kalidou Koulibaly from Napoli this summer.
Given the unrest surrounding the players and owner Aurelio de Laurentiis, Napoli could sell Koulibaly. The 28-year-old may be sold to generate funds.
Koulibaly is a world-class defender and he would be a massive signing for the Red Devils. He would be a perfect defensive partner for Harry Maguire, who has established himself as United captain since arriving from Leicester City for a record £80m last summer.