Chelsea are renowned for their excellent youth setup, which has seen multiple players progress and excel within the Blues' first team.

Reece James, Conor Gallagher and Levi Colwill are just three examples of talents who are currently within Mauricio Pochettino's side that progressed through the Cobham academy.

Fiakyo Tomori and Mason Mount were in the Chelsea youth sides around the same time as the names previously mentioned, with the pair eventually leaving Stamford Bridge and making the club a huge profit.

The youngsters both enjoyed successful spells at Derby County before returning to the club, making an impact, then ultimately being sold for £25m and £55m respectively.

However, the club also let another talented youngster depart, with the former Blues player now an established Premier League talent with multiple international call-ups.

Marc Guehi's stats at Chelsea

After joining Chelsea as an eight-year-old, defender Marc Guehi rapidly progressed through various youth levels at Stamford Bridge, helping the U18 side win the quadruple.

He signed a professional contract at the age of 18, before enjoying multiple loan spells at Swansea City in the Championship. He was part of the Swans side that lost the play-off final in 2021 against Brentford, with Guehi "brilliant all season" – in the words of Steve Cooper – and attracting interest from multiple Premier League sides.

Upon his return to Blues after his successful stints in south Wales, it was unclear whether the centre-back would stay at Stamford Bridge or depart on loan once more, enabling him to gain valuable first-team minutes.

Chelsea decided against both options, with Thomas Tuchel selling the youngster to another Premier League side – a move that looked brilliant business at the time, but now a huge mistake.

Marc Guehi's transfer value in 2024

Guehi was sold for £18m to Crystal Palace in the summer of 2021, with the defender signing a five-year deal at Selhurst Park.

He's excelled since the move, with the now 23-year-old looking to be worth every penny of the transfer fee spent on him. He's made 108 appearances for the Eagles, with the former Chelsea youngster being an integral part of the Palace squad, taking the armband in recent months.

His excellent form away from Chelsea hasn't gone unnoticed either, with Guehi receiving his first England call-up in March 2022 and making his debut for his country in the 2-1 win over Switzerland.

The 6-foot centre-back has since featured nine times under Gareth Southgate, with the defender's market value increasing rapidly as a result.

In 2024, the 23-year-old is now valued at £32.5m as per Transfermarkt – a figure that is £7m more than Chelsea left-back Ben Chilwell, with the defender valued at £25.5m – less than four years after his £45m move to Stamford Bridge.

Given his rapid rise since his departure, the club could regret selling the “absolute tank” – as dubbed by by former England U21 teammate Josef Bursik – with the Blues potentially saving a lot of money had they stuck by the academy graduate.

Indeed, the Blues may well be blessed with plenty of options in the centre of defence with Axel Disasi and Benoit Badiashile acquired under Todd Boehly's ownership but Guehi is now Premier League-proven and would have saved the American a fortune had he not been sold.