One of the most common debates on social media is which club in Europe has the best academy. Many people believe Barcelona’s La Masia academy reigns supreme. They have produced so many legendary players, including Lionel Messi, Xavi and Andres Iniesta, to name three.

Then, you have those who argue it is Manchester United’s academy. There is perhaps no group more famous than the Class of 92, which included the likes of Paul Scholes, David Beckham and Gary Neville, or more recent talents including Marcus Rashford and Kobbie Mainoo.

However, the one youth system that is perhaps the most consistent in recent years is Chelsea’s famous Cobham Academy. Cobham graduates include the likes of Ray Wilkins, John Terry, and, more recently, Mason Mount, all of whom have done great things in the game for Chelsea.

However, Chelsea’s Cobham system also produces plenty of players who go on to have a great career away from Stamford Bridge.

These players include the likes of Tammy Abraham, now playing in Italy with AS Roma, and Dominic Solanke, who is currently on 17 Premier League goals for the season.

However, there are two academy products that the Blues may regret selling, with their values and ability on the pitch continuing to skyrocket in recent seasons. They may well regret losing the two players more than they did Antonio Rudiger, who has gone on to be a key player for Real Madrid since he left Chelsea.

Rudiger’s exploits at Real Madrid

31-year-old Rudiger joined Real Madrid on a free transfer from Chelsea in the summer of 2022, ahead of the 2022/23 transfer window. It was a frustrating move for Chelsea, who failed to convince the German to sign a new deal at the club.

Since the move, Rudiger has won four titles, including the Club World Cup and the Copa Del Rey. He is still chasing his first La Liga title at the Santiago Bernabeu, but Real Madrid are eight points clear at the top of the league.

Not only that, Los Blancos have a Champions League semi-final to look forward to against Bayern Munich. They beat Manchester City on penalties, with Rudiger the man to score the winning penalty, calmly slotted away past Ederson.

He has put in many a strong performance in the famous white shirt since joining Madrid. According to Fbref, Rudiger is one of the best aerial defenders in the world. He averages a 67% win rate per 90 minutes for aerial duels, which ranks him in the top 18% of centre-backs in Europe. He has become a crucial player under Carlo Ancelotti in Madrid.

Rudiger not the only centre-back Chelsea will rue selling

The two Cobham graduates that Chelsea may regret losing more than Rudiger are Marc Guehi, now at Crystal Palace and Fikayo Tomori, now at AC Milan.

The Blues sold Guehi for £20m and Tomori for £25m. Between them, Guehi and Tomori are now valued at £51m, which is around £25.6m each, as per Football Observatory.

Guehi is one of the most progressive players in the Premier League. His long passing is a standout feature of his game, and he is strong on both feet. As a central centre-back in possession in a back three, he can really show this off, being able to play lots of long balls. In fact, as per Fbref, the 6.37 long passes he completes per 90 minutes rank him in the top 15% amongst centre-backs in Europe.

These numbers stack up well in favour of Guehi against Chelsea’s most-used defender this season, Axel Disasi, who they paid £38.7m for from AS Monaco. His 3.68 long passes completed per 90 minutes as per Fbref rank him as low as the 29th percentile. He is a slightly different profile to Guehi, and not as strong when playing long passes, but it is still a stark difference.

Tomori is a wonderful box defender, which is reflected in his stats, courtesy of Fbref. The 1.67 blocks he makes per 90 minutes place him in the top 14% amongst defenders in Europe respectively. When compared to Disasi, the numbers are in favour of Tomori. The Frenchman averages 0.98 blocks per 90 minutes, which ranks him in just the 16th percentile.

Both Guehi and Tomori are now key players for their club and could well have become important players at Stamford Bridge had they had the chance to stay.

Chelsea must surely regret moving both of them on and flying to keep Rudiger, because either defence could look a lot different now, had things gone differently.