Concerns like this seem to be normal especially when looking at Chelsea's performance this season especially with the majority of players in attack and midfield now new and the coach also new will certainly give concerns about the chemistry that is woven.
At present, Chelsea have brought in several new players who are expected to really fit in with Chelsea and make the quality of their game even better, and be able to enter the UCL again next season. Because their failure in mysim makes them learn a lot. But can they bounce back like they did with Barcelona?