In the past 24 hours there has been a backlash against Gabriel and his family, for the direction he is taking and around his professionalism and attitude.

Sources close to the player believe this is massively unfair and overlooks the dedication and commitment which means he is so well-regarded by so many clubs.

In addition, he is not the first young player to have a difference of opinion over their future direction with their club.

Jadon Sancho was 17 when he stopped training at City to force through a £10m move to Borussia Dortmund in the belief that he would play more often in Germany than under Pep Guardiola.

Morgan Rogers was Barry’s team-mate in the West Brom side that reached the FA Youth Cup semi-final in 2019. Within three months he had left for City, a move completed on his 17th birthday.

Sources feel that, in meetings with the United hierarchy that led to Gabriel committing his short-term future to the club last summer, promises were made over his career path that have not been kept.

He did start to appear in senior training sessions, initially under Ruben Amorim and then Michael Carrick, but speculation around a senior debut last season, which could only be in the FA Cup, was doused by Under-18s coach Darren Fletcher, who had by now taken the senior team manager’s role on an interim basis following Amorim’s dismissal. Fletcher felt it was too early for Gabriel.

It had been anticipated that Gabriel would feature during United’s pre-season programme.

His absence from the trip to Helsinki for a meeting with Wrexham on 18 July was put down to the date he returned for pre-season training.

He was part of every squad after that, but played only once, for eight minutes against Atletico Madrid in Stockholm.

Did that lack of action sow the seeds of discontent? Gabriel travelled to Trondheim for a meeting with Rosenborg on 24 July. Carrick used 11 substitutes that day. Gabriel was one of two United players who did not come on. Five of those who did have left, either permanently or on loan.

It was noted that 18-year-old Tynan Thompson was given a 45-minute senior debut against Leeds United at Croke Park – another game Gabriel travelled to but was not involved in – three weeks after his arrival from Tottenham.

Nevertheless, it was felt Gabriel was likely to become United’s youngest player this autumn – probably in the EFL Cup.

While the third-round draw delivered an Old Trafford rematch with Brighton, United’s Champions League schedule opened up another avenue.

It is conceivable that Azerbaijani champions Sabah could be the least difficult home game Carrick’s side have this season.

United were 3-0 up at half-time and Carrick had used all five substitutes by the 72th minute.

But Gabriel was not among them. As with Max Dowman at Arsenal last season, Uefa’s registration rules meant that, because he was 15, Gabriel could only feature if he was named on United’s A list of players.

It is not entirely clear why that did not happen. United named a maximum of 25 players, but among them was midfielder Manuel Ugarte, who will not play until after the registration window opens again in January because of a knee injury. Thompson was also on the list.

United coaches have previously suggested that Gabriel is not yet at the physical level required to be a senior player. Sources close to the player reject this.

Instead, they see how Arsenal gave Dowman his chance at 15 and Bayern Munich gave Lennart Karl his debut at 17, and wonder why United are not doing the same.