The Giallorossi have been negotiating with United for much of the summer for Smalling, one of their best players last season.
However, the club’s financial state meant Roma risked missing out on the 30-year-old when United asked for €20-€25m.
Roma’s patience looks to have paid off as they are now close to signing ‘Smaldini’.
Sky Italia reports that Roma will sign Smalling on another paid loan with an obligation to buy him.
The deal will be worth a total of €12m, far lower than what United have been requesting for the centre-back.
Much of this is down to Smalling, who has ‘pushed hard’ for a return to the Italian capital.
Talks have yet concluded, but there are positive signals and Roma hope to close the operation quickly.
Smalling will sign a three-year contract with Roma and head coach Paulo Fonseca will have one of his leaders back.
Perez could also arrive
The 20-year-old Argentine spent last season on loan at Famalicao in Portugal, making a good impression.