The two sides have been locked in negotiations and are hoping to get a deal in place before Monday’s 11pm deadline.
Chris Smalling’s proposed permanent move to Roma looks set to hit late stumbling block
United’s asking price is set to have shifted from £13.6million to £16.3m, with the additional money being made up in a series of installments.
Smalling is understood to be pushing for the move to happen, after setting well in the Eternal City last year.
The Old Trafford central defensive partnership is now established between captain Harry Maguire and Victor Lindelof, with Eric Bailly still on United’s books.
Smalling has spent the past few weeks training alone at United’s Carrington training base, working on his fitness while hoping a deal can be concluded.
There remains talk of defender Diogo Dalot also being included in a possible deal
Further speculation has arisen regarding the potential inclusion of full-back Diogo Dalot in a deal.
Roma are said to be willing to stump up additional cash if they are able to take the Portuguese defender as part of the deal.
Dalot has also been heavily linked with a move to the San Siro to sign with AC Milan.
United have two days remaining to strike an agreement, while also still holding out their own faint hopes of signing Jadon Sancho from Borussia Dortmund.