Twenty years, 426 appearances, 138 goals and five trophies later, Marcus Rashford is set to leave for Aston Villa.

It will seem strange to see Rashford – the boy from Wythenshawe, United through and through – wearing another team’s strip.

As recently as November, the idea seemed fanciful.

How did we get here?

Even towards the back end of last week, there was still hopeful talk of a resolution on Rashford’s part. Now the reality is sinking in. Amorim has got his way.

What has been very difficult to pinpoint, even though Amorim has given some frank interviews, is the detailed reasoning why the coach was so willing to let him leave.

It was all sparked when Amorim dropped Rashford for the Manchester derby on 15 December.

Three days earlier, the forward had been substituted 11 minutes into the second half of what looked like being an embarrassing Europa League defeat by Czech side Viktoria Plzen.

Rasmus Hojlund came on to replace him and scored two goals to turn the match into a 2-1 win.

Rashford his been omitted from 11 of 12 squads since.

The one time he did make a squad – the 2-0 home Premier League defeat by Newcastle on 30 December – he was left on the bench. Afterwards, Amorim was asked why.

When he had to address the subject again before Thursday’s Europa League win over Romanian side FCSB, Amorim seemed as if he was starting to get irritated.

There is no doubt he has used the Rashford situation as a test of his strength. Sir Alex Ferguson, an illustrious predecessor, may well have approved.

“If the coach has no control, he will not last,” Ferguson explained in a case study for Harvard Business School, published in the weeks after his retirement in 2013.

“You have to achieve a position of comprehensive control. Players must recognise that as the manager, you have the status to control events. Before I came to United, I told myself I wasn’t going to allow anyone to be stronger than I was. Your personality has to be bigger than theirs.”

Amorim’s latest comments on the Rashford saga were not as polished but the sentiment was the same.

“You [the media] want to make it personal,” said Amorim. “I have nothing against Marcus but I have to make the same rules for everybody.”

It was more or less the same message Amorim delivered at the Etihad Stadium in dropping Rashford and forward Alejandro Garnacho for the Manchester derby win over City.

In various forms, it has been repeated at least half a dozen times in the interim.

“It’s important, the performance in training, the performance in the games, the way you dress, the way you eat, the way you engage with your team-mates, the way you push your team-mates, everything is important in the context of beginning something, when we want to change a lot of things,” Amorim outlined.

“It’s the small details. When people in our club are losing their jobs, we have to put the standards really high.”

Rashford responded to that forceful assertion by using a visit to his old school to tell football writer Henry Winter he was ready for “a new challenge”.

That was widely interpreted to mean the player wanted to leave. But sources close to Rashford explained that, as they understood it, he was voicing a general feeling of frustration rather than a desire to try something new.

They say he felt he was being eased out of a club he remained attached to – a club he felt he knew far better than those running it.

Club sources say Rashford has trained well. Unlike Jadon Sancho, who fell out with former United boss Erik ten Hag, again over standards, Rashford was not banished to a different area of the Carrington training ground and told to change on his own.

While Rashford’s body language has not always presented the most positive image, recent open training showed a different side.

During the 15 minutes session broadcast before the Europa League matches against Rangers and FCSB, Rashford was expressive and light-hearted.

When Amorim ‘ran the gauntlet’ through the first-team squad to mark his 40th birthday, Rashford was among those in the line, smiling after the United boss had charged through.

It has never been plain sailing for Rashford at United.

A succession of managers have felt at times that they were not getting the most out of a player with blinding speed, excellent balance and an eye for goal.

For the 2022-23 season, the first under Ten Hag, Rashford was diligent, going to the United States for personal sessions to ensure he was ready to go when the real preparations began.

The reward was a career-high 30 goals. It is a strike rate no-one else in the United squad can match and is the chief reason why representatives spent time visiting some of European football’s biggest clubs – Barcelona, AC Milan, Borussia Dortmund – gauging interest and trying to work out what kind of a deal was possible before the transfer window closed.

But was the goals output confirmation of Rashford’s talent or the exception amid more mediocre returns in recent times?

The season before, he found the net twice in his final 28 appearances. Since August 2023, he has scored 15 in total. The drop off is alarming. Even sources close to the 27-year-old accept he is not playing well.

However, despite missing the past 11 games, he is still United’s joint-fourth highest scorer this season with seven, the same as £72m signing Hojlund, who has played four more games.

Only Amad Diallo (six), Bruno Fernandes (five) and Hojlund (four) have scored more goals under Amorim than Rashford (three), who has only been on the pitch in 35% of the new head coach’s games at United.

United’s record goalscorer Wayne Rooney has told Rashford in private he should leave. It is an observation he offered to a wider audience on The Overlap podcast.

“I’ve spoken to Marcus a couple of times,” he said. “I’ve given him my thoughts. I’ve said: You need to leave the football club.

“I went into Carrington to take my kids to game day and Marcus was out on the training pitch with the fitness coach, right over towards where the parents were walking past for the kids’ games. I remember looking at him thinking: How embarrassing is it that the parents are walking past?”

Rooney’s former United team-mate Rio Ferdinand used similar terms to describe how he would feel if a manager had called out his training performances as Amorim had to Rashford.

“My heart, my pride, my ego. It’s embarrassment,” Ferdinand said.

“For someone to question you giving 100% for the team, saying you’re lacking effort and taking shortcuts: That’s a damning comment. There’s no way back for Marcus after that.”

One theory floated by a source with an understanding of the workings at Old Trafford pointed to financial matters.

Rashford and Casemiro – who has not been omitted from Amorim’s squad like the England man but has played only three times since the Plzen game – are by far United’s highest earners. The theory is their presence makes it difficult for United to get their profligacy in the transfer market under control.

If they left, representatives of prospective signings would be unable to use them as a benchmark for wage negotiations.

Consequently, it is not until those salaries are off the books that United can properly start to move forward in a more sustainable manner, without the threat of profit and sustainability breaches hanging over them. Those rules also feed the view that homegrown stars such as Alejandro Garnacho and Kobbie Mainoo might need to be sold.

United have grown used to subsidising moves for highly paid players who not reaching the standards required and no longer wanted by the manager of the day. Their wage bill is one of the highest in world football. Few would say United have been getting value for money.

Alexis Sanchez, Donny van de Beek, Romelu Lukaku, Anthony Martial and Sancho have all fallen into that bracket.

Rashford is the next one out, with United believing they have done well to negotiate a deal that, they say, covers 75% of his wages.

Sources close to the player were adamant the interest in him was huge.

There were offers from the Saudi Pro-League, but he felt accepting might mean abandoning his England career.

A big ambition was to join Barcelona, but they needed to offload players to make it happen. That scenario never materialised into anything close to reality.

So Villa, emboldened financially by the £71m sale of Jhon Duran to Al-Nassr, made their pitch.

There is plenty about the switch that makes sense. Villa’s status is currently greater than that of United. They are pushing for a top-five slot, despite Saturday’s defeat at Wolves, and have a Champions League last-16 game in March to look forward to. Unai Emery needs someone who can play through the centre, if required, or in a wide slot. Although he prefers to be on the left, Rashford can do all of this.

Emery, it is being stressed, was a huge selling point. On a personal level, Rashford doesn’t need to move house.

So the lifelong Manchester United fan, who felt so entwined with his team, will now wear the claret and blue of Villa, at least until the end of the season.

As for Amorim, he has made the big call. He no longer has to answer questions about a player who belongs to another club.

But he needs to deliver success himself. If he doesn’t, and Rashford does well, he will be in a very uncomfortable position.

Sources have told BBC Sport talks are at an advanced stage, but there is work to be done to finalise the move.

The prospect of working with Villa boss Unai Emery is understood to be an attractive one for the 27-year-old.

Rashford has not featured for United since being dropped by head coach Ruben Amorim for the Manchester derby on 12 December.

Last week Amorim suggested he would rather give a place on the bench to his 63-year-old goalkeeping coach because of a perceived lack of effort by the striker.

On Wednesday the United boss said he felt his side would be better with Rashford in it, but the player had not met the standards he demands of his squad.

“Imagine a talent like Rashford, our team should be so much better with him – but he has to change,” explained Amorim.

“If he changes, we are more than welcome [to include him] – and we need it. But in this moment we have to set some standards. We are waiting for Rashford, if he wants it really bad.”

Rashford has been with United since the age of seven, made more than 400 appearances, won the Europa League, two FA Cups and two EFL Cups.

He scored in Amorim’s first game in charge, a 1-1 away draw at Ipswich on 24 November, before netting twice in a 4-0 win over Everton a week later.

But the forward was left out of the squad for United’s 2-1 victory at Manchester City on 15 December and subsequently told journalist Henry Winter he was “ready for a new challenge”.

Villa have signed Spanish full-back Andres Garcia from Levante and Netherlands forward Donyell Malen from Borussia Dortmund so far in this window.

On Friday, they sold Colombia striker Jhon Duran to Saudi Pro League side Al-Nassr in a deal that could be worth up to £71m.

They have also rejected an approach from Arsenal for their England striker Ollie Watkins.

The Midlands side are currently eighth in the Premier League and finished in the top eight of the new Champions League group stage to qualify for the last 16.

He has not said it publicly, but Ruben Amorim did not want this version of Marcus Rashford around. Rashford has known it, hence his “new challenge” comments last month.

But if he accepts a challenge so close to home, the outcome will be fascinating.

If Rashford starts scoring at Villa under Unai Emery – and United continue to struggle in that department – questions will be asked of the head coach at Old Trafford.

Rashford has huge talent, while Emery is a vastly experienced coach. If anyone can unlock the forward’s abilities he can.

With a top-five place and a Champions League campaign ahead of them, Villa have more going for them than United right now.

There will be some people shuffling uncomfortably at Old Trafford if Rashford helps Villa achieve their objectives.

Former Manchester United and Aston Villa striker Dion Dublin says the deal would be a “great move” for Rashford.

He told Football Focus: “It is such a stable club with a very, very good manager. There would be some world-class players around him and he would be going into a very happy camp.

“Marcus needs a big hug and for someone to tell him, ‘Listen, you’re an excellent player’. I think Unai Emery could be the coach to get the best out of him. Let’s see what happens.”

Former Arsenal forward Ellen White added: “A move to Aston Villa would be something new and fresh for Marcus Rashford. We know he can be a great goalscorer and he is a great player. He just needs something different, a new environment.”