They've had their fair share of injuries too.
Enciso was out for ages, only just back. Started his 3rd game of the season.
Mitoma and March have been out a while now. March has played 7 games this season.
Webster has played 9 games.
Estupinan was out for a while too.
All of these players are key players who would start most games if fit.
There's just no consistency for them, only three players have started over 20 games. Partly De Zerbi's fault too as he likes to rotate even without injuries, but some of the replacements just aren't good enough.