The full-back was left out of United's 18-man squad to face West Brom on Saturday and afterwards United boss Mourinho blasted the 21-year-old's fitness and attitude.
Having been made aware of the criticism on Sunday evening, it is understood that Shaw held a meeting the following day with Mourinho to discuss those comments at the Aon Training Complex, and the talks appear to have led to a breakthrough after the England defender was seen checking into United's team hotel ahead of Tuesday night's Premier League clash.
Where next for Luke Shaw?
Where next for Luke Shaw?
1/6 Where next for Luke Shaw?
Shaw has struggled for first-team opportunities at United under Jose Mourinho and hasn't played since starting against Bournemouth at the beginning of March. Mourinho says Shaw is a 'long way behind' his teammates throwing his future firmly up in the air. So with a move in the summer now looking increasingly likely, where could he go? We weigh up his options (all odds provided by Betfair).
2/6 Tottenham (5/2)
Tottenham are the early favourites for Shaw and with Manchester City said to be circling Danny Rose you can understand why. Mauricio Pochettino has worked wonders with a number of England’s next generation at White Hart Lane and Shaw could relish the opportunity to work with a coach who is ready to put his arm around him and the Argentine would surely like to nurture a player he already knows well from his time at Southampton.
3/6 Everton (4/1)
Everton already have a fine left-back but Ronald Koeman knows Leighton Baines isn’t getting any younger and could be ready to look for his replacement. The Toffees and United have made willing bedfellows too in recent years and a deal could benefit both sides with Everton having money to spend this summer.
4/6 West Ham (6/1)
Shaw is a big name so of course West Ham would be linked with him. Again, they have an excellent left-back already in Aaron Cresswell but co-owners David Gold and David Sullivan may once more be seduced by the flashy move.
5/6 Stoke (8/1)
Stoke have quietly built an impressive squad in recent years and a move for Shaw would fit what they are now trying to put together at the Bet365 Stadium. Mark Hughes would love to work with a player of Shaw’s quality and the 21-year-old would help lower the average age of a squad which remains on the older side.
6/6 Crystal Palace (8/1)
Despite shelling out some £12m on Jeffrey Schlupp in January Sam Allardyce would surely be in the mix for Shaw's signature should he indeed become available. A switch to London could also appeal to the player as he bids for a change of scenery and fortunes.
Record signing Paul Pogba, who has missed United's last two games with a hamstring complaint, was also present.
Shaw's future at Old Trafford appeared bleak when Mourinho said he was "a long way behind" his team-mates.
Mourinho added: "I cannot compare the way he trains, the way he commits, the focus, the ambition."
That prompted former United full-back Phil Neville to tell Shaw to "pull his finger out" to save his Manchester United career.
Neville felt Mourinho was simply trying to give the player a "jolt" - a theory which will look increasingly likely should he be involved against Everton.
"If I was Luke Shaw, I wouldn't be looking to get out of Manchester United," Neville told Press Association Sport on Monday.
"I'd be looking at that situation thinking that on Saturday (Mourinho) played Ashley Young at left-back, that he has been playing Matteo Darmian at left-back, Marcos Rojo, Daley Blind. These are players who are not out-and-out left-backs.
"So rather than thinking 'the manager doesn't rate me', I'd be thinking 'I have to pull my finger out here' and think the opportunity in front of me is absolutely huge, to be the number one left-back at one of the biggest clubs in the world.
"Something has to change for Luke Shaw, because someone with that ability has got to be England and Man United's number one left-back, and if he's not, then there is something fundamentally wrong.
"The comments coming from Jose Mourinho suggest there may be an attitude problem or a professionalism problem, and if that is the case, this could be the kick up the backside he needs.
"He needs to probably take a long hard look at himself and realise the opportunity that is in front of him.
"In life, you only get one opportunity at a club like Manchester United, and if you don't grasp that opportunity, you end up being sold and going maybe back to Southampton, thinking 'should have, would have, could have'."
Phil Neville was speaking as part of the 2017 McDonald's Football Mum of the Year award about the impact mums have on grassroots football. Nominate a deserving mum now at http://www.mcdonalds.co.uk/awardsReuse content