The Belgium international was wanted by his former club Chelsea but is set to join Jose Mourinho as the Red Devils' second summer signing, according to the Telegraph. Victor Lindelof was the club's first signing.
The 20-time English champions had been looking at the option of signing Chelsea's Nemanja Matic in strengthening their midfield. However, the report claims the Premier League winners are unlikely to allow the Serbian international join United after they hijacked their deal for Lukaku.
Mourinho's side will then force their attention to Dier, who was their primary midfield target in the summer transfer window. United have still not given up their hope of signing the 23-year-old, who signed a new five-year deal last September and is currently earning £75,000-a-week ($96,735 per week).
United's initial bid for Dier has already been turned down by the north Lonon club. The Red Devils' executive vice-chairman Ed Woodward and Tottenham chief Daniel Levy have continued talks over a possibility of signing the England international.
Spurs chairman has refused to put a price tag on Dier, but there is a belief that a bid of around £50m ($64.5m) will see the London outfit listen to offers. A move to United will see the former Sporting man double his wages, meaning he will earn £150,000-a-week ($193,470 per week).
Tottenham are not in a position where they have to sell their star players this summer. Dier has played in 36 league games for the White Hart Lane club, while most of them have come when he was deployed as a defender in a back three.
Mauricio Pochettino deployed Mousa Dembele and Victor Wanyama in the central midfield position last campaign. Dier, who can play in the defence and in the midfield, prefers to play in the centre of the pitch. A move to United will help him play in his preferred midfield position.
The Telegraph also claims that Dier's position in Tottenham's XI next season is not guaranteed as the club looks to bring in a new defender. They have identified Swansea City's Alfie Mawson and are considering an option of bringing him in the ongoing window.
Swansea have slapped a £30m ($38.7m) price tag for Mawson, which Tottenham are unwilling to pay. There is belief that the Welsh club are likely to lower the fee if the Premier League runners-up can offer Josh Onomah on loan as a part of the deal.