The early signs have been concerning. Even after Chelsea made a late change to their first-choice goalkeeper, replacing Robert Sanchez with Emi Martinez, they have continued to concede too many goals. Chelsea have allowed two goals in every match so far apart from their Carabao Cup tie against Luton Town.

That is becoming increasingly difficult to overlook given the progress made at the other end of the pitch.

Alonso has inherited – and helped develop – an attack that looks significantly sharper, with Chelsea’s forward options providing plenty of encouragement. The next stage of his work could therefore involve shifting some of that attention towards a defence that has yet to show the same level of reliability.

There is an acceptance that the midfield must offer better protection but sources say a new defensive upgrade in 2027 is possible. 

Maxence Lacroix, signed in the summer, is viewed positively inside the club and there is a belief that the French defender will prove to be a good addition. And Chelsea will have teenager Honest Ahanor arriving, too. He signed from Atalanta and has joined Crystal Palace on loan. 

However, Chelsea are expected to continue exploring the market for another defender who can bring qualities that are currently in short supply, such as composure, technical ability and leadership.

At this early stage, there are initial signs of the type of player Chelsea could target. Flashscore sources have identified Jarrad Branthwaite and Giorgio Scalvini among the names being discussed as the club considers options for the future.

The emergence of those names illustrates the level of defender they could be looking for as Alonso assesses his squad. And that process will also put pressure on the current group to improve.

Wesley Fofana is one player who may need to raise his level if he is to remain an important part of Chelsea’s long-term plans. There is an acceptance of his ability, but sources say his future will come under greater scrutiny if he cannot establish greater consistency.

For Chelsea, the priority is not simply to add another centre-back. The bigger objective is to build a defence capable of matching the quality and ambition of the attacking unit Alonso is developing.