It takes a lot more than talent alone to make it in the world of football.
Sure, it definitely helps but if that talent is not coupled with a desire to work hard, to live a healthy lifestyle, have the right attitude and, of course, a double-helping of good old-fashioned luck then it's all too easy to fall between the cracks in the cutthroat world of the beautiful game.
The sport is littered with players who have failed to deliver on the promise shown early in their careers. For every Lionel Messi or Cristiano Ronaldo, there are dozens of players who showed similar promise but, be it through injuries, a bad attitude or a lack of application in training, they never reached the heights that they seemed capable of.
Here are ten players who looked like they would develop into world beaters but ultimately failed to deliver.
Michael Johnson
Michael Johnson was tipped to be the finest player to have emerged through the Manchester City youth system in many years. His introduction to the first team was seamless and when the central midfielder was handed the club's #6 jersey and it was expected that he would be a fixture in the middle of park for City for the next decade and, as if to underline their faith in him, the club rejected a big money offer from Liverpool for the player when he was still a teenager.
Unfortunately for all involved, Johnson's career failed to take off past this point. His career was beset by injuries and personal problems - a double hernia operation removed him from first-team duties and he never truly regained his fitness. City, now bankrolled by the Abu Dhabi takeover of the club, invested heavily in the team and the path back to the starting XI was now blocked by several big-money imports.
Johnson made his final appearance for Manchester City in 2009 - just his fourth competetive appearance in his final five seasons with the club and he retired in his mid-20's. He now works as an estate agent.
Ricardo Quaresma
https://youtu.be/fQjgQcdWaFs
It might seem strange to include a player who just won the European Championships with Portugal in this list but Ricardo Quaresma's career is a textbook case of player failing to live up to his billing. He was once described by Cristiano Ronaldo as having more talent than him when they were young players. Why, then, has Ronaldo gone on to become one of the finest players of his generation and Quaresma became little more than an afterthought?
A thrilling player with the ball at his feet, Quaresma was a Portuguese champion with Sporting Lisbon when he was just 17 years old. A big money move to Barcelona followed but what would be a dream move for most youngsters ended up being a nightmare and his move to the Catalan giants was the start of a very pronounced downfall. He was moved back to Porto a year later where he revitalised his reputation before José Mourinho spent £21 million to bring him to Inter Milan - where he would be voted the worst player in Serie A.
The Portuguese now lines up for Besiktas in the Turkish league, hardly a powerhouse of European football.
Francis Jeffers
https://youtu.be/Zt0lvKfm4Dg
An old-fashioned 'fox in the box' striker, Francis Jeffers was hailed at one time or another by the likes of David Moyes, Arsene Wenger and Sven Goran Eriksson as being potentially one of the greatest goalscorers of his generation and, for a while at least, it was easy to see why.
Emerging from the same Everton youth system which would produce Wayne Rooney, Jeffers bagged 21 goals in his first 60 games for The Toffees and still is, to this day, the joint top scorer in English U21 history with 13 goals in 16 appearances. He then went on to score a goal in his only appearance for the English national team.
These initial two paragraphs are about where the story ends for Francis Jeffers. Arsene Wenger, famous for unearthing youth talents across the globe, plucked Jeffers away from Everton before he had completed his development with the club who had nurtured him since he was a young boy. He was never the same again.
Jeffers slowly dropped down the league system to Charlton, Blackburn and Sheffield Wednesday before lining up in the Australian and Maltese leagues. He retired three years ago while on the books of Accrington Stanley (who are they?)
Still, he does have a 100% goalscoring record with England. Not even Bobby Charlton can say that.
Freddy Adu
Freddy Adu is one of the most infamous stories of unfulfilled potential in football. Adu was prophecised as being the biggest prospect that football in the United States had ever seen, becoming one of the first youngsters to go 'viral' on the internet. Adu joined DC United in the MLS at just 14 years of age and was thrust directly into the first team.
It was considered only a matter of time before the Ghanian born teenager would be lining out for Real Madrid or Manchester United. Instead, a decade after his debut, he had spells with the likes of Caykur Rizespor in the Turkish league, as well as turning out for football powerhouses like Bahia in Brazil and Jagodina in Serbia.
Almost a dictionary definition of the term 'over-hyped', Adu was clearly a good underage player and you would have to wonder what might have become of him had he not been designated as the chosen one of United States football and devloped in a more traditional environment.
Denílson
https://youtu.be/QbwB_o4fPho
Denílson, not to be confused with the defensive midfielder at Arsenal who also failed to impress, was at one point the world's most expensive footballer when he moved from Sao Paulo to Real Betis in 1998 for what was then the mind-boggling fee of £21.5 million.
The thing is, Denílson was never really that good. He was a nifty left winger who owned great pace, a decent left foot and a fleetness of foot which would sometimes leave defenders planted on their arses - but that was about it. He wasn't necessarily a gamechanger in the same manner that future world's most expensive player Paul Pogba has, or even close to posessing the same level of skill that, for example, Gareth Bale displays for Real Madrid and Wales.
It wasn't long before he was considered a flop in Spanish football and his career descended in journeyman status - he would line up for various teams in France, Saudi Arabia, United States and Vietnam before hanging up his boots in 2010.
Liam Miller
https://youtu.be/5UHpeXs3q1E
'It's Miller Time' was proudly pronounced by one of Ireland's red tops ahead of Liam Miller's Ireland debut back in 2004, such was the excitement ahead of his an Irish debut which had been delayed by a few niggling injuries. And why wouldn't they be excited? Miller had made a name for himself with some excellent displays in Glasgow, so much so that Martin O'Neill had intended to build his entire Celtic side around the Corkman.
You know what they say about best laid plans though. O'Neill's ideas of Miller being the centrepiece of his Celtic side for the next decade were scuppered whent he youngster agreed a pre-contract deal with Manchester United after Alex Ferguson recognised Miller's ability to pull significant strings in the middle of the park.
But, as with so many other players on this list, his move to England's most successful club failed to ignite Miller's career like he might have imagined. Miller left Old Trafford to move to Roy Keane's Sunderland after appearing in just nine league games in two seasons. He can now be seen in the shirt of the Wilmington Hammerheads in the Eastern Conference of the third tier of the United States football pyramid.
Neil Mellor
When Neil Mellor swung his right foot at the ball in the dying moments of what was at the time a 1-1 draw at Anfield with Arsenal, it seemed that a new hero of the Kop had been born. His connection with the ball was Gerrardesque and, as the ball swerved inside the corner of the goal from 30 yards out, it seemed Neil Mellor had the world at his feet.
Unfortunately for Mellor this was to be the highlight of his entire football career. He was from the same Anfield assembly line which produced Robbie Fowler and Michael Owen and, for a spell at least, it seemed that Mellor's name might be whispered in the same reverential tones as his two predecessors. Instead, his career took him to West Ham and Wigan on loan before a permanant transfer to Preston North End yielded a handful of semi-successful seasons in the Championship.
He'll always have that winner against Arsenal though.
Jermaine Pennant
Jermaine Pennant was tipped for supertardom from a young age. Arsene Wenger paid £2 million to Notts County for Pennant's services when he was just 15 years old - a record for a trainee at the time, though he would make just 26 appearances in six seasons at Arsenal.
Pennant comes from the time-honoured tradition of a young footballer going off the rails as a result of having 'too much, too soon' and has a litany of off the field problems as if to prove this point. In 2004, Pennant wrapped his car around a lampost and identified himself as Ashley Cole when the police arrived. Pennant also joined the very exclusive list of footballers who were forced to play with an electronic tag on his leg as a result of being convicted of drink-driving for this incident and for not, in fact, being England's left-back.
In 2011 while playing in Spain, Pennant was notified that his car which he had left at a local train station had gathered five months worth of parking tickets. Pennant's excuse? He forgot he owned the car, though at least he wasn't Ashley Cole this time around.
Pennant, who is Irish qualified, now lines up in the Singaporean league and we don't think Martin O'Neill and Roy Keane are terribly interested in checking up on him.
Adrian Doherty
The Class of '92 produced some incredible talent for Manchester United and forged the spine of a side which would go on to dominate English football for over a decade. David Beckham, Paul Scholes and Gary Neville would go on to become world famous players and win practically everything you can win in the club game but there is one name who emerged from that same group of players who you might not be so familiar with - Adrian Doherty.
Doherty was considered every bit as talented as his academy teammates. In fact Paul Scholes, Ryan Giggs and the Neville brothers have said that Adrian Doherty was the best player they ever saw at youth level. So what went wrong?
At age 16, and just a few days before he was scheduled to make his first team debut at Manchester United, Doherty suffered a cruciate ligament injury - an injury which removed him from football for two years and robbed him of the natural attributes which had separated him from his peers. He moved to Derry City where he played a handful of games before retiring from the game, still in his teens.
He later moved to Amsterdam where he fell into a canal. After a month in a coma, Doherty died the day before his 27th birthday.
Adriano
As anyone who has played Pro Evolution Football will tell you, Adriano had one hell of a left foot. All you had to do in one iteration of the game was to pass the ball to Adriano, get it on his left foot and you would have a decent chance of scoring from practically any distance.
In real life though, Adriano's career was blighted by infuriating inconsistency. At his best he was arguably the finest striker in the world but as his career progressed and his weight ballooned, instances of Adriano being 'at his best' became few and far between.
His career produced a series of blistering performances and outstanding goals prior to his 24th birthday but he was unable to maintain any sense of consistency and, much like so many others on this list, he was forced to play at level later in his career which would have seemed improbable given the prodigious level of skill he displayed just seasons before.
See More: The Curious Case of Ravel Morrison, The Man Who Was Tipped To Be Better Than Paul Pogba
