Why do Chelsea look short in midfield?

What happened

The primary issue is the absence of midfielder Moises Caicedo, who is out with an unspecified injury for an unknown period after breaking down just 11 minutes into a substitute appearance against Brighton last week. It has left Xabi Alonso in almost uncharted territory for a Chelsea boss. Aside from suspensions, Caicedo had missed only two matches during the previous three seasons, through a knock and illness.

Summary assembled by rule from the sources below

Sources