Dean Huijsen needed barely half a season at Bournemouth before Real Madrid spent £51million to trigger his release clause. Ilya Zabarnyi set Paris Saint-Germain back even more, up to £57million.
Combined, that is £108million for Andoni Iraola's starting centre-backs. Aged 20 and 21 respectively, Huijsen and Zabarnyi have made an enormous profit from a relatively small sample size.
Huijsen, in particular, had to wait until injuries opened up a place in the side. He finished with just under 2,500 minutes (plus stoppage time) having started four senior games in Europe prior to last season.
That sort of rise is what Chelsea were willing to pay big money for earlier this summer. They were one of a number of teams interested in the Spaniard but lost out as Madrid had his heart.
What does this have to do with the opening weekend of the Premier League season? Bournemouth are one of the teams still interested in taking Josh Acheampong from Stamford Bridge as they look to revamp a decimated defence that also lost Milos Kerkez to Liverpool.
There is a genuine comparison to be made between Acheampong and Huijsen as well. When watching Bournemouth go 2-0 down at Anfield on Friday night with new-look pairing Marcos Senesi and Bafode Diakite both struggling to deal with the movement and speed of Hugo Ekitike, Chelsea's position with Acheampong took on a different light.
This article contains affiliate links, we will receive a commission on any sales we generate from it. Learn more
This is a club that knows how to develop players quickly and is willing to trust them. Compare Bournemouth last season, throwing Huijsen and his raw potential into the team during a fitness crisis, and Chelsea, as they barred Acheampong from playing for either the senior or academy sides for almost three months whilst pushing for him to sign a new contract.
In the end, Acheampong committed himself until 2029 but the process was uncomfortable. If there is anything close to that level of uncertainty again then Acheampong would only be right to consider his options.
In what was still a breakout year (13 appearances as an 18-year-old defender for a team on the way to finishing fourth and winning two trophies is a good start), Acheampong found himself outcast during a period of opportunities in the Conference League. He effectively lost out on four group phase games that would have been ideal starting ground, as well as plenty of time on the training pitch with his new teammates.
Before long, Acheampong was a fully fledged member of Enzo Maresca's squad and he has continued to grow in that time. It is a testament to his mental strength that he overcame isolation as a teenager and went straight into the squad without as much as a hitch.
He is among the numerous centre-back options for Maresca now and is taking on an increasingly important position with injuries around him. Levi Colwill's long-term absence through knee rehabilitation has opened up a spot that Acheampong is eager to take. Although he is not a like-for-like on the left side, both Tosin Adarabioyo and Trevoh Chalobah have shifted from their right-sided role to cover.
That opens up room for Acheampong to play more, essentially seeing him go from fourth choice to first over the weekend. When all are fit, Acheampong is still further down the pecking order but he is taking his chance.
On Sunday, Tosin was ruled out through a muscle problem that Maresca did not feel able to comment on with a timeline. He started alongside Chalobah and took on the responsibility in the middle of Chelsea's three-man defence when in possession.
It was the area that Maresca spoke animatedly about before the match. He has expressed his views that there are no suitable replacements when Colwill and Tosin are unavailable. Acheampong tried his best to politely say 'hold my beer.'
Against Crystal Palace, ironically the team who he made his surprise full Premier League debut against in January, he was trusted with dealing with the imposing presence of Jean-Phillipe Mateta. Between the two, Chalobah and Acheampong did a pretty good job.
Mateta had one big chance but was otherwise kept quiet on a day where Chelsea and Palace frustrated each other. Palace did more of the stalling but were still allowed very few clear routes to goal themselves.
Acheampong was part of that, although he was not able to add the same punch that Colwill or Tosin do when passing. His game is very much via dribbling, something he does better than maybe any other centre-back at Chelsea.
Wesley Fofana is similar in the way he progresses play. They are both perhaps more suited to being on the right of the three but Maresca has had to make do here.
Acheampong regularly took the ball past Palace's first line of press, bypassing Mateta, only to then be extremely safe in his next action. That may well be because two of his more adventurous moments almost cost Chelsea.
For a game in which Acheampong reminded everyone of his talent and laid down a genuine marker as to his position in this squad, especially at a time whereby there is a disagreement between recruitment staff and manager over buying a new centre-back, he did still have a few nervy moments. After all, it was his errant pass forward that found Eberechi Eze in the move which resulted in the foul for the controversially disallowed free-kick goal.
Chelsea and Acheampong got away with that one and were fortunate that Eze chose to try and lob Robert Sanchez from more than 40 yards when another poor pass was intercepted, setting up a dangerous Palace attack. Eze made the wrong choice, like Acheampong, and let Cobham graduate off the hook.
Outside of these two mistakes it was a composed performance from a player still finding his feet. In a perfect tackle on Daniel Munoz, Acheampong made use of his impressive frame and long reach to stop a cross whilst he had the second most touches of anyone on the pitch. Only Chalobah had more, and Acheampong completed 80 of 86 passes over the afternoon.
There is still plenty of room to improve for Acheampong, who is a better passer than he showed here. Chelsea will now be monitoring Tosin's fitness ahead of the trip to West Ham on Friday.
Fofana is still getting up to speed and hasn't played since March. Benoit Badiashile will not be back until after the international break in September, whilst Jorrel Hato is not yet viewed as really being a centre-back.
This leaves a gap for Acheampong to assert himself. Despite Maresca publicly calling for yet more reinforcement, Acheampong is doing his part to stake a claim for an increased role in the squad this season.
Chelsea know the damage and danger of not offering out minutes to academy players after losing Marc Guehi in 2021 to Palace. The club, who were under Roman Abramovich's ownership when Guehi was sold, will be wary of repeating that sort of deal.
The same goes for Tino Livramento and Lewis Hall, both of whom have proven themselves to be extremely valuable for Newcastle United. Acheampong has had more of a step into the senior game than either really got at Stamford Bridge and now the challenge is to keep him there.
Want to keep up to date with the breaking and important Chelsea stories whilst on the move? Well now you can!
Click this link to follow the football.london Chelsea WhatsApp channel, where you'll be kept up to date on the latest Blues news wherever you are.
Just remember to turn on the notifications once you've followed, and you won't miss a beat!