However, the Blues should not be in despair, Chelsea fan ExpectedChelsea wrote on Twitter.
The fan has conducted a statistical analysis which shows that one of Chelsea's loan players has a very similar profile to Tchoaumeni.
"It's remarkable how similar Aurelien Tchouameni 2020/21 is to Ethan Ampadu 2021/22," ExpectedChelsea tweeted.
"Both terrific ball-winners, decent progressive passers and great athletes. They were the same age during the respective seasons too.
"We might have an underrated gem on our hands. The similarity between Tchouameni and Ampadu is uncanny. Spooky, almost.
"He did not get much hype because his team was pretty terrible but statistically, he jumps out of the screen."
To prove the point, ExpectedChelsea posted a graph comparing key stats from both players' performances in their respective seasons.
The wheelchart below shows that Ampadu still has areas where he can improve (like pressure regains progressive carries), but he holds his own in terms of tackles, recoveries and aerial duels.
The fan continues: "Tchouameni is better - you don't need a graph to tell you that - but I'm very impressed by how close Ampadu is despite playing for a much worse team. Monaco were 3rd in France, Venezia were 20th in Italy.
"Keeping Ampadu is a better option than buying a sub-par 'depth' player.
"A midfielder from the worst team in Italy has absolutely no business being this close to a midfielder who was already a star in France. This is incredibly encouraging stuff."
Ampadu has been described as promising for a few years already - but he is still only 21 years old and has a lot of years ahead of him. Could Chelsea make a top-level player out of him?