Roma are understood to value the Greece international at over £50 million, with Jose Mourinho’s side keen to secure his services in the January transfer window.
Manchester United are set to bid £47.6 million for Roma defender Kostas Manolas, according to The Sun.
United have been heavily linked with a move for Benfica’s Victor Lindelof, but Mourinho has also sent scouts to watch the 25-year-old Greece international.
Roma value Manolas at £52m, and are unlikely to budge from their valuation of one of their prized assets.
The Manchester United manager has said he does not intend to buy another defender but behind the scenes is still working on a deal for the Greek international.
The Manchester United coach Mourinho had initially coughed up £32.5m for Manolas.
That came after talks with Victor Lindelof hit a wall – despite Benfica and Vasteras recently agreeing a sell-on fee.
And last May, when Mourinho started looking at which players he would like to sign, he paid special attention to Manolas and team-mate Alessandro Florenzi.
But Roma, who currently sit just four points behind Serie A leaders Juventus, are reluctant to lose one of their most sought-after assets.