Jose Mourinho is keen follow up the signings of Victor Lindelof and Romelu Lukaku with a third summer arrival, thought to be a defensive midfielder. Wide-ranging reports have suggested Dier, 23, has been the club's preferred choice for that role but according to the Observer, the club will now turn their attention elsewhere after seeing three bids for the England international rejected.
United's executive vice chairman Ed Woodward has approached the north London side three times this summer with bids of £25m, £30m and another close to £40m, according to the report. But on each occasion, his Tottenham counterpart Daniel Levy has told him a sale is out of the question.
Dier is reportedly open to joining United after he was displaced as Tottenham's first-choice defensive midfielder by Victor Wanyama last season, spending much of the campaign filling in across the backline.
But the report adds Dier "has not allowed the situation to affect him", with Mauricio Pochettino impressed with what he's seen from the former Sporting Lisbon youngster so far during pre-season.
United have also been linked with Monaco star Fabinho this summer to fill that midfield role, but IBTimes UK understands the Brazilian is now unlikely to join a Premier League side this summer.
Chelsea midfielder Matic has now emerged as the favourite to fill that void at Old Trafford. Wide-ranging reports suggest Blues owner Roman Abramovich has now sanctioned his £50m sale after the Premier League champions rejected an initial offer of £35m.
The arrival of France international Tiemoue Bakayoko has paved the way for the Serbian's departure from west London with Mourinho keen to renew his working relationship with him having initially brought him back to Chelsea from Benfica in 2014.