Chelsea have long been criticised for seemingly stockpiling hot prospects and sending them out on loan after limited first-team opportunities.
A number of stars may consider themselves unfortunate after failing to break through in west London, with a highly-rated youngster recently adding to the growing list of those who have fallen by the wayside.
Despite his rapid rise to becoming one of Serie A's most exciting young players since joining Sassuolo, Chelsea have rejected the chance to trigger Jeremie Boga's buyback clause.
The club, perhaps eager to avoid past mistakes, had inserted a £13million option into the deal to take him to Italy - but they have turned their attentions elsewhere ahead of the upcoming transfer window.
Boga progressed through Chelsea's youth academy, but was handed just 18 minutes to stake his claim in the first team before being shipped out for several loans. He completed the permanent switch to Italy in 2018.
Here, Sportsmail takes a look at other former Chelsea academy stars who failed to make the grade at the club...
BERTRAND TRAORE
Lyon's flying winger Bertrand Traore embarked on his very first steps to stardom with Auxerre, before it was reported that he had moved to the Chelsea academy in August 2010. It was even suggested that he had snubbed Manchester United.
But, to plunge his future into further confusion, Chelsea confirmed in January 2012 that Traore wasn't, and never had been, their player.
He had appeared once for the club's youth team as part of a six-week trial earlier in the season, and was forced to wait until October 2013 to officially pen his contract.
The transfer was completed in January 2014, and the very next day Traore was sent out on loan to Vitesse Arnhem. After impressing in Holland, it was confirmed the now 24-year-old would remain with the club again for the following season.
Traore earned a work permit in June 2015, and therefore had clearance to play for Chelsea during that campaign. Despite a handful of appearances, and several goals, the winger endured a quiet season and was soon shipped out to Ajax on loan.
The youngster netted four Europa League goals during the club's run to the 2017 final, and played 90 minutes in the defeat against Manchester United. But despite Traore impressing on the European stage, Chelsea chose to pull the trigger and sold him permanently to Lyon in 2017.
Traore has racked up more than 50 caps for Burkina Faso, having made his debut aged just 15, and enjoyed good form in France. However, recent reports indicate his time at Lyon may be coming to an end this summer with Rudi Garcia frustrated with the star's inconsistency.
OLA AINA
Ola Aina is another hot prospect to have endured a nightmare spell attempting to break into Chelsea's first team. His frustrations were perhaps summed up across the course of 45 minutes of pre-season football in 2014.
Chelsea faced off against AFC Wimbledon in July, and Aina was handed his debut at the highest level for the club. Todd Kane's injury had allowed his fellow starlet a precious shot at the big time, but Aina was instead substituted at half-time for Branislav Ivanovic.
The Premier League club went on to win 3-2, and Aina struggled to make an impact over the months that followed. He had signed for Chelsea as an under-11, and made his youth team bow as a schoolboy in the 2012-13 season.
Aina also started both legs of the semi-final and final of the FA Youth Cup.
Aina penned a new four-year contract in July 2016, putting an end to rumours that he was set to leave the club.
And over the following months, Chelsea boss Antonio Conte ensured he earned ample rewards for his loyalty.
His professional debut came against Bristol Rovers in the EFL Cup, and Aina was also handed his maiden Premier League appearance against Leicester the following month.
But despite his initial breakthrough, Aina joined Championship outfit Hull on loan for the 2017-18 campaign. And following his spell in the second tier, the 23-year-old then moved to Torino in Serie A.
His impressive form saw the club take up the option to turn the deal permanent for a reported £9m.
NATHAN AKE
Dutch stalwart Nathan Ake joined the Chelsea youth system aged 15 from Feyenoord in 2015 - and just two years later, the centre back was handed his Premier League debut.
His run of sporadic appearances that campaign continued, with Ake selected in a holding midfield role for Chelsea's Europa League quarter-final tie with Rubin Kazan.
The youngster survived the encounter in Russia, helping Chelsea progress to the next round despite the defeat suffered that evening.
He was an unused substitute for the final of the competition, and unsurprisingly voted Chelsea's Younger Player of the Year in May. Following the news, Ake penned a new five-year contract.
But the highly-rated defender was then loaned to Championship side for Reading for one month, making five appearances, and featured just once more in the league at Chelsea during the rest of the campaign.
Ake was once again handed a bumper new five-year deal, and spent the following season with Watford.
After several commanding displays for the Hornets across the back line, Bournemouth swooped in June 2016 to take him on loan. Their move paid dividends, with the Dutchman the unlikely hero in the club's dramatic 4-3 victory against Liverpool on the south coast.
Chelsea recalled the player back in January, but Ake soon returned to the sunny beaches of Bournemouth in a £20m club record deal.
The centre back has long since been regarded as the club's most valuable asset, and earned a clean sweep of Player of the Season gongs for the 2017-18 campaign.
RHIAN BREWSTER
Rhian Brewster was spotted by scouts from an array of clubs at the tender age of seven - with Chelsea, Arsenal, West Ham and Charlton believed to have been circling for the promising youngster.
The now 20-year-old opted to join Chelsea, however, and developed while progressing through the London outfit's academy.
But, as many starlets appear to be faced with at Chelsea, Brewster reached a crossroads and was forced to make a mature decision. His choice would influence the rest of his years on the field, and Brewster instead headed to top flight rivals Liverpool.
He said: 'There was nothing special or different about that day. It was after football, and as usual, my dad and I spoke about how it went and the areas I wanted to work on.
'We then got talking about players who were doing well at the academy and ones that had done so in the past.
'I realised all the names we were mentioning hadn't played for Chelsea's first team and there didn't seem to be a chance for those still at the club to get promoted to the seniors.'
Aged just 19, Brewster was able to boast about his achievements - having been part of winning squads in the 2018-19 Champions League, 2019 UEFA Super Cup and 2017 Under-17 World Cup.
But after joining Liverpool, Brewster has struggled to make an impression on the first team and joined Swansea on loan this season before the coronavirus crisis called the action to a halt.
DECLAN RICE
Current West Ham star Declan Rice started his career with Chelsea as an infant. He was selected for the Blues' academy at the age of 16, but, along with a number of his peers, was released eight years later.
Rice has recently revealed his shock at being axed from the ranks at Chelsea, saying: 'That was everything I ever knew to be honest. From nine to 14, training there Monday to Friday, playing games and to get told you won't be a part of that anymore was a major shock. I never thought it would have to happen but it did.'
But rather than let the disappointment consume him, Rice headed to east London to join the youth system at West Ham.
His decision paid off spectacularly. Rice worked his way through the ranks, and made his senior debut for the club in 2015 aged 18.
His rapid rise to becoming one of English football's hottest prospects was cemented last season, with Rice rapidly becoming a fan favourite due to his versatility and relentless energy in midfield.
Rice earned his 50th appearance for West Ham in December 2018, the first player to do so while still a teenager since Michael Carrick.
His impressive form also allowed him to pledge his international future to England in February 2019 - with his debut under Gareth Southgate arriving just the next month.
The Three Lions star's future at West Ham has recently been called into question again, however, with Manchester United said to be keen to sign him. Chelsea have also been linked with a reunion with their former academy star.
NATHANIEL CHALOBAH
Watford midfielder Nathaniel Chalobah is another youngster who opted to leave Chelsea in search of regular first team football, and even admitted his frustration with the sheer amount of loan spells he was sent out on.
The now 22-year-old progressed through the Chelsea academy, but spent short-term spells with six different clubs before deciding to walk away in 2017.
'Being at Chelsea, I would have signed a new deal and gone out on loan again and got frustrated,' he said.
'That was the choice I had to make, but it was emotional leaving Chelsea. The conversation I had with the manager Antonio Conte was positive but it was a decision I had to make after being on loan six times.'
After the parting of ways, Chalobah moved to Vicarage Road for a reported £5m fee on a five-year deal - and having made just 15 appearances in total for Chelsea.
Just days after the talented star's departure was confirmed, the Stamford Bridge outfit confirmed the signing of Tiemoue Bakayoko in a further indication of the uphill struggles starlets can face at the club.
Chelsea spotted Chalobah as a 10-year-old and nurtured his talent across the space of 12 years. The midfielder earned 97 England caps at various levels, but his efforts culminated in just one Premier League start and nine substitute appearances.
He had regularly captained both the reserve and youth sides at Chelsea after penning professional terms in 2012, but was largely forced to make a name for himself during loan spells with Watford, Nottingham Forest, Middlesbrough, Burnley, Reading and Napoli instead.
Source: m.allfootballapp.com