After the final whistle sounded at Craven Cottage on Sunday, Kobbie Mainoo strolled on to the pitch, dropped down on his haunches and contemplated having watched Manchester United’s first two games of the new Premier League season entirely from the substitutes’ bench.

Mainoo looked just as downbeat and ruminative as he quietly boarded United’s team bus for the trip home later that evening, his head hung low.

You did not need to be a body language expert to see that — according to those familiar with the situation, speaking on condition of anonymity to protect relationships — he has been left deeply frustrated by not featuring in either of United’s matches this season so far.

Still, this is nothing particularly new. Questions over Mainoo’s playing time and his role within Ruben Amorim’s system have abounded for months.

As a result, the 20-year-old United academy graduate is open to leaving his boyhood club before the transfer window closes on Monday, having discussed as much with team-mates. United, meanwhile, have been considering the prospect of selling him all summer, sources say.

Although not part of the four-man ‘bomb squad’ alongside Alejandro Garnacho, Antony, Jadon Sancho and Tyrell Malacia, who have trained separately following their returns to United’s Carrington base to begin pre-season, Mainoo — like striker Rasmus Hojlund — has been identified internally as a potential departure since the start of the window in June, and the club have been willing to sell him at the right price since as far back as January.

United sources insist they are not actively pushing Mainoo out the door, however, and staff are happy with him, albeit, like all players, he has areas to improve. People at Old Trafford expect him to remain a United player beyond next week’s deadline, with the caveat that anything can happen in the final days of a transfer window.

Mainoo is said to be training well at United (Ash Donelon/Manchester United via Getty Images) But aside from the pursuit of Carlos Baleba, a dream target who is considered too expensive to prise away from Brighton & Hove Albion this year, United’s summer-long search for a midfielder has focused more heavily on identifying an alternative to Bruno Fernandes. Somebody who would play alongside either Casemiro or Manuel Ugarte. One who would, in effect, replace Mainoo within the squad, as per Amorim’s latest description of his role.

Bayern Munich explored the possibility of a move for Mainoo but did not formalise their interest. New Bayer Leverkusen manager Erik ten Hag would have liked to reunite with a player he championed and promoted while in charge at Old Trafford, but a deal was thought to be out of the German club’s reach financially.

Mainoo is thought to prefer moving to the continent rather than staying in the Premier League — he explored options in Germany when coming through United’s academy — even though there has been interest from closer to home. When Chelsea enquired about his availability during the January window, Stamford Bridge officials were quoted a £70million asking price. There is a belief United would now accept around £45m, potentially even less as the deadline draws near.

Whether other exit routes open up for Mainoo between now and Monday night remains to be seen — he has also been linked with Tottenham Hotspur — but if he stays or goes, the fact is a local-born academy graduate is closer to leaving than ever for two principal reasons: his struggles for regular playing time under Amorim, and an impasse in discussions over a new contract.

Mainoo signed a four-year deal, with the option of a further year, in February 2023. At the time, he had only made two senior appearances, starting in a Carabao Cup quarter-final tie against third-tier Charlton Athletic, then coming on as a substitute in a FA Cup fourth-round against Reading, then of the second-tier Championship.

His first and only Premier League appearance that season — an 11-minute cameo against relegation-bound Leicester City — was still a few days away, and so the salary offered by United was typical for an academy talent with potential to break through into the first-team squad.

And yet a little more than a year later, he had established himself as a regular under Ten Hag, playing 32 games and scoring five times, including what proved the winner in a famous 2-1 FA Cup final defeat of Manchester City.

Then came his first major international tournament call-up with England, starting four games under Gareth Southgate at that summer’s European Championship, including the 2-1 loss to Spain in the final.

Mainoo was a regular in England’s run to the Euro 2024 final (Justin Setterfield/Getty Images) That rapid ascent is why even some who know Mainoo well can sympathise that, at a potentially critical juncture in his career, the next step is a difficult one to navigate for both the player and the club.

Mainoo is currently paid around £20,000 a week. Conversations over a new, extended deal have taken place over the past year and have understandably centred around a hike to that salary.

As a key player for the club, Mainoo was hoping for a substantial improvement to his terms — potentially up to 10 times those present wages. At one stage, he was starting in midfield ahead of Casemiro, a player on around £350,000 per week when United are in the Champions League. But the club were reluctant to meet that outlay even when he was playing regularly, believing he would only be ready to move up to such a pay grade after another year or two of development.

Right now, the prospect of any new deal looks remote. Those familiar with the situation say Mainoo currently has no intention of renewing, given his playing opportunities under Amorim. His willingness to leave was initially thought to be a bargaining position by many at the club but it has become a possibility, if not this summer, then in a future window.

Few players in Mainoo’s position would commit themselves to a club where they were not sure of regular minutes anyway, and concerns that the 20-year-old does not have a clear pathway to more game time within Amorim’s system are more relevant now than ever.

Ruben Amorim has doubts over Mainoo (Matt McNulty/Getty Images) Amorim reiterated on Sunday that Mainoo’s direct rival for a place is currently Fernandes — the club captain who started all but five of United’s 60 games in all competitions last season, and is set to predominantly play in midfield rather than at No 10 in this one after the summer arrivals of Matheus Cunha and Bryan Mbeumo.

This reconfiguration of the squad has pushed Mainoo to the fringes. But his minutes, and particularly his opportunities in central midfield, were diminishing long before Cunha and Mbeumo arrived. After missing most of November appointment Amorim’s first few weeks in charge through injury, Mainoo started as part of the two-man midfield pivot in six of United’s seven games from mid-December to mid-January, up until the 3-1 loss to Brighton at Old Trafford.

From then on, Amorim began deploying Fernandes in midfield more regularly, and experimented with Mainoo as a No 10 and a false nine. He did not start in midfield again before picking up another injury in February during a week of heavy training at Carrington, sidelining him until early April.

Once he returned, Mainoo’s only starts came as part of rotated line-ups in games before or after United’s critical Europa League knockout ties with Lyon and Athletic Club. Across those four legs, he played 59 minutes of a possible 390 — mostly during the extra-time period against Lyon, when he was introduced as an 86th-minute substitute, then scored a 120th-minute equaliser.

Despite that dramatic goal, and although United were trailing Tottenham throughout the second half, he was only a substitute again in the final itself, brought on in the 90th minute. His first competitive appearance since that match could come tonight (Wednesday) in the Carabao Cup second round tie away to fourth-tier Grimsby Town.

So why has Mainoo suddenly fallen out of favour, particularly as an option in midfield? Mobility is said to be one area of his game that Amorim has targeted for improvement. The manager said this summer that Mainoo needs to “increase the pace, the rhythm” of his play. “I’m always on top of that with Kobbie because he’s so good sometimes, but he can be better,” Amorim added.

When Mainoo returned to training after recovering from that injury in the spring, many at Carrington noted he had bulked up physically during his spell on the sidelines, adding more muscle mass to his then teenage frame, leading some to question whether that would help or hinder his agility.

There is an argument that, at his age, rotation-level minutes should be expected. United have arguably placed too much responsibility on young shoulders in the past. It should not be forgotten that Amorim was an international midfielder himself, playing 14 times for Portugal, and knows that you do not peak at such an early age.

Yet some figures close to Mainoo have been left dumbfounded by his fall from favour and surprised by a lack of communication from Amorim. Rather than provide specific instructions, the 40-year-old’s general attitude to concerns about playing time is to tell players to train hard and earn their spot. That applies to all of his squad, not just Mainoo — Casemiro found favour again after being out of the picture.

Mainoo celebrates scoring against FCSB last season (Vasile Mihai-Antonio/Getty Images) Yet whether it is the best approach for youngsters who require guidance and feedback is questioned in some quarters.

Mainoo, for his part, is said to be doing the right things and quietly going about his business around Carrington. He is close to fellow youngster Leny Yoro, with the pair doing fitness work together during the summer and also being seen socialising in Manchester.

The season is still only two games old, as sources at Old Trafford are keen to stress, and Amorim has repeatedly said there will be opportunities for younger players and those on the fringes further down the line. Yet those opening games have only demonstrated how difficult it will be for a talented academy graduate, who is immensely popular with supporters, to earn regular minutes in his best position. And, importantly, during a World Cup year, too.

In the two league games to date this season, when Amorim has turned to his bench with United searching for either an equaliser or a late winner, he chose to bring on Ugarte and Harry Maguire against Arsenal, and Ugarte, Maguire and Ayden Heaven at Fulham, apparently preferring players who could offer a threat from set pieces over Mainoo’s skill set.

There is also the connection with United’s youth record that Mainoo represents. There has been an academy graduate in every United senior matchday squad dating back to 1937. He was the only one in the 20 for last season’s Manchester derby against City at the Etihad Stadium, and should he leave, a run that stands at 4,323 games could be broken.

Mainoo’s rise has been fast, perhaps so accelerated that a period of readjustment was inevitable at some point, but there is increasingly a sense that it has now stalled, and further progress may only be possible away from his boyhood club.

Additional reporting: Adam Crafton

(Top photo: AJ Reynolds/Getty Images)