The name of Ravel Morrison was catapulted back into the wider footballing consciousness recently when Wayne Rooney lauded his talents when coming through the ranks at Manchester United.
It served as a reminder of just how exceptional the teenage Morrison was on the football pitch but also of just how much has to perfectly align for someone to make it at the elite level.
Quite a few United stars have lamented the 'lost' talents of the midfielder but Morrison is far from the only player at Old Trafford singled out as something special at a young age only to find the path to stardom blocked.
United's academy production line is quite rightly regarded as one of the world's best, with a steady stream of players making the first team grade over the past 70 years.
But by the law of averages, not everybody can make the leap and often it comes down to injuries, distractions outside of football or simply the challenge of trying to break into an exceptional team.
Sportsmail takes a closer look at Morrison and some of the other highly-regarded players who didn't become first-team regulars at United.
RAVEL MORRISON
Almost every prominent United player who witnessed Morrison's incredible skill in training came away singing his praises.
In his Sunday newspaper column, Rooney recalled seeing him nutmeg defender Nemanja Vidic three times in the space of a minute.
Rio Ferdinand recalled the time manager Sir Alex Ferguson called him over to watch a 14-year-old Morrison and declared him 'the best player he had seen at that age.'
Ferguson said that Morrison was better than Rooney and Ryan Giggs were at a similar age.
Ferdinand himself said 'I would pay to watch him train let alone play in a match', while Gary Neville described his ability as 'scandalous' and akin to the class of Paul Gascoigne.
In 2011, Morrison was part of a United youth team also containing Paul Pogba and Jesse Lingard that won the FA Youth Cup and later that year made his first-team debut in the League Cup.
But while Pogba and Lingard - albeit circuitously - would become present-day United stars, Morrison slipped away into a nomadic career that took him first to West Ham and then Lazio, not to mention spells in Mexico and Sweden.
Morrison is currently on loan at Middlesbrough in the Championship, from parent club Sheffield United.
But unfortunately it was off-field issues that restricted Morrison to just three senior appearances for Manchester United, with the player lucky to escape a jail sentence for witness intimidation in 2011.
'He possessed as much natural talent as any youngster we ever signed, but kept getting into trouble,' Ferguson wrote in his 2015 book, Leading.
'The problems off the pitch continued to escalate and we had little option but to cut the cord.'
As Morrison, now 27, himself admitted this week following Rooney's comments: 'It makes you a bit upset that I could have gone a bit further. I should have gone a bit further. I'm hoping still to go a bit further.
'I knew I had ability, but I didn't realise and understand.'
BEN THORNLEY
United's Class of 92 has passed into football folklore, with David Beckham, Ryan Giggs, Paul Scholes, Nicky Butt and the Neville brothers stalwarts in Ferguson's teams for a decade or more.
But one of the most accomplished members of that youth side, perhaps the one most commonly tipped for a top-class career at Old Trafford, was destined not to make it.
Winger Ben Thornley was drawing the loftiest comparisons as he progressed through the youth ranks.
United legend Nobby Stiles said of him: 'Ben is the closest I've seen to George Best in all my time at the club.' Sir Matt Busby, Best's manager at United, was sitting close to Stiles when he made that statement and didn't argue otherwise.
Beckham said that Thornley 'would have outdone us all', Scholes recalled he was 'a step above all of us, he could do everything' and Neville thought 'he was one of the most outstanding talents I ever played with.'
But it wasn't off-field distraction that did for Thornley, but a cruel twist of fate. Aged 18, he suffered a horror tackle from Blackburn defender Nicky Marker in a reserve match in April 1994.
Suffering a ruptured medial collateral ligament and medial capsule, ruptured cruciate ligaments and a detachment of the medial meniscus, Thornley lost a crucial year.
Though he returned to play 13 times for United, his career was irreversibly set on a trajectory that would take him to the lower leagues rather than the constant success achieved by the other Class of 92 members.
It took Thornley a long time to overcome the mental scars of being so violently thrown down this alternative career path. He was plagued by alcohol abuse while playing for Aberdeen in 2006 but managed to turn his life around.
Thornley wrote about the ups and downs of his life in an autobiography called 'Tackled: The Class of 92 star who never got to graduate' in 2018.
ADRIAN DOHERTY
One of the most poignant and ultimately tragic tales of what might have been at Old Trafford.
Just a few years before the Class of 92, Adrian Doherty was also being billed as the new George Best and not just because he hailed from Northern Ireland.
Described as a right-sided Ryan Giggs, but even more talented, Doherty was the boy who was going to propel Alex Ferguson's United to the next level.
'I had never seen anything like him before,' Giggs recalls in Oliver Kay's excellent book on Doherty's life and times 'Forever Young'.
'Once he was out on the pitch, he was incredible. He was the quickest I had ever seen and he was so brave as well. He was an incredible talent. Incredible.'
Ferguson described him as 'the quiet boy with the most amazing football skill' and was all set to hand Doherty a first team debut in 1990 and then again alongside Giggs in 1991.
But days before, playing in an A team fixture against Carlisle United at The Cliff, Doherty stayed down after a 50-50 challenge and damaged his knee.
He never recovered sufficient fitness to take another leap at the United first team, he never made a senior appearance, and another factor was Doherty's bohemian character.
A creative and artistic soul, he often seemed more infatuated by the songs of Bob Dylan and busking on the streets of Manchester than entertaining crowds at Old Trafford.
In the end, he drifted away from football, returning home to Strabane before busking in pubs in Galway before moving to Holland in pursuit of work.
On the morning of May 7, 2000, he slipped and fell into a canal in The Hague. Doherty had a phobia of water and couldn't swim. Dragged out unconscious he died on June 9 after over a month in a coma. He was 26.
MADS TIMM
There were high hopes for this Danish wonderkid when United signed him as a 16-year-old from Odense in 2000.
The forward was part of the United team that won the FA Youth Cup in 2003, beating Middlesbrough, having already been rewarded with a professional contract.
And Timm duly made his first-team debut in October 2002 when a youthful United side were mauled 3-0 by Israeli team Maccabi Haifa in the Champions League, having already assured their passage to the quarter-finals.
Unfortunately, a year later Timm found himself fighting for his place with a certain Cristiano Ronaldo, signed as a 17-year-old prodigy from Sporting Lisbon.
'He was just the opposite [to me]; he was moving forward, clear-headed and with an indomitable faith in himself,' Timm wrote in his book Red Devil.
'Every time we met on the field, he wiped me, and I have rarely been so out of breath after a test. He pulled the air out of me.'
It has become clear that Timm didn't have the temperament to succeed at Old Trafford and because of his own stupidity, that one appearance would remain his lot.
In January 2004, Timm and his United team-mate Callum Flanagan were involved in a high-speed car race that ended in a crash as they left the Carrington training ground.
Timm was driving a high-powered Mitsubishi Evolution and Flanagan was in a Honda Civic travelling at speeds of between 60 and 65mph in a 40mph speed limit.
It was heard in court that 'these two foolish young men were involved in a race at high speed during which they gesticulated towards each other using abusive gestures.'
The two cars collided into a third, causing injuries to a woman, and the judge, sentencing Timm to a year in a young offenders' institute in March 2005, said it was 'pure luck no one was killed.'
Flanagan was immediately sacked by United but Timm wasn't and remained on their books until May 2006 when he was released and returned to Odense.
RODRIGO POSSEBON
Alex Ferguson had built up United's scouting operation in South America during his time in charge and their Brazil-based scout John Calvert-Toulmin had unearthed the Da Silva twins, Fabio and Rafael, who played regularly at Old Trafford.
Another promising youngster signed from Brazil around that time was Possebon, a 19-year-old central midfielder who had cost £3m to buy from Internacional.
That area of the field had become an issue for United ever since Roy Keane had quit a couple of years earlier, with the injury-afflicted Owen Hargreaves the closest they'd come to anyone matching Keane's influence and work-rate.
When Possebon arrived at Old Trafford, however, Ferguson had no qualms about labelling him the 'natural successor' to the Irishman while other hyped him into the new Paul Scholes.
As he impressed in Ole Gunnar Solskjaer's reserve side, director of the academy Brian McClair said: 'Rodrigo is a tall, elegant midfielder who fits into the idea of a modern footballer. He has very good ability and is a box-to-box player rather than your silky tricky midfielder.'
By the start of the 2008-09 campaign, having impressed in pre-season cameos, Possebon was handed the No 34 shirt by Ferguson and looked ready to launch his bid for that deep-lying midfield role in the side of the European champions.
He duly made a couple of substitute appearances in the Premier League but a career-changing moment was just around the corner. And not in a positive way.
Named in the starting XI for a League Cup game against Middlesbrough, Possebon was crunched by the raised studs of Emanuel Pogatetz and landed in a crumpled heap.
The Brazilian needed six minutes of oxygen treatment on the pitch before being taken to hospital and fortunately his leg wasn't broken. 'I hope I never see anything like it again,' fumed Ferguson.
But how quickly the hype over a young player dies down. By the end of the season, Possebon had lost all momentum and was soon out on loan to Braga.
He played just once in Portugal and returned significantly further down the pecking order. In the summer of 2010, United sold Possebon to Santos and he returned to his homeland.
Now 31, he last played for the Vietnamese club Ho Chi Minh City.
DONG FANGZHOU
The case of Dong Fangzhou, the brightest footballing talent of his generation to emerge from China, is certainly a curious one.
When he signed for United from Dalian Shide in January 2004, for an initial fee of £500,000 which could have risen to £3.5m, he was hailed by chief executive David Gill as a player of 'outstanding quality' who could 'become one of the best young players in the world.'
While United were at immense pains to stress the possibility of selling millions of replica shirts in China was not the reason behind buying him, Gill did admit his arrival would 'open innumerable possibilities for the club in the Chinese market' before adding 'but the deal is sporting as much as commercial.'
Unfortunately the culture shock for Dong, who couldn't speak any English, was enormous and things were complicated when his ineligibility for a work permit meant a loan to United's Belgian feeder club Royal Antwerp.
He performed well there, however, and whetted the appetite for his belated arrival in Manchester in early 2007, when Ferguson hailed his 'speed and physicality' and called him an 'explosive talent.'
United even enlisted the help of the owner of Wing's restaurant in the city - later to become the favourite of Louis van Gaal - to help Dong settle in.
His Premier League debut came against Chelsea but as part of a second-string side with the Premier League title already secured.
Though he hung around the following season, making a handful of additional appearances, it was apparent Dong wasn't going to match the hype.
As team-mate Darren Fletcher told The Athletic: 'You're talking about a stage and a time at Manchester United where the competition for places was crazy.
'But there was something there with Dong. He was aggressive, he was quick, he had a great shot. He had attributes.'
What happened next is even stranger. Dong embarked on a nomadic career that included time back at Dalian Shide, a brief stint in Poland with Legia Warsaw, time in Portugal with Portimonense, Armenia with Mika and then a return home to China.
Nonetheless, he still won 13 caps for China during his time on United's books.
Bizarrely he was then spotted on a Chinese reality TV series about having plastic surgery on his bloated face after what appeared to be years of excess.
Source: m.allfootballapp.com