However, they are open to negotiating with United over a summer move.
We'll have to wait and see whether that turns out to be the case but the Croatian global would be an excellent addition to the United squad if they do manage to lure him to Old Trafford this summer.
Dier, who admitted in 2010 while at Sporting Lisbon that it would be hard to turn down United if the chance came to join the club he supported as a boy, has been Mourinho's No1 midfield target this summer and Levy may face a dilemma when United's offer is broken down.
Mourinho is apparently willing to go up to £60 million for Dier although it seems likely that Levy will push him further for an England worldwide.
The 23-year-old Dier is a vital part of the Spurs team.
The 29-year-old has impressed in the Italian league with 14 goals last term to help fire Roma into the Champions League group stages.
"He's one of their two main midfield targets".
The Express claim they have already rejected United's £45m offer and sporting director Piero Ausilio recently insisted that they were not interested in selling Perisic this summer. He knows Mourinho would play him in his favoured role.
Spurs are willing to allow Kyle Walker to head to Manchester as Pep Guardiola seeks to strengthen his City defence, but his situation is different to Dier's.
Perhaps Mourinho, in his race to finish the post-historical chapter of the book where Manchester United waltzes to the Premier League title in 2017-18, has forgotten a key detail from the past.