What do the aforementioned injuries have to do with lack of rotation?
Bernal had a contact injury after a nasty foul. The question might be whether he should be playing and how much, but certainly not overdone yet.
Christensen played less than half an hour and has a chronic injury.
Nothing...
Pretty obvious it's not his fault the club gave him such a big contract and his right to exercise it.
Anyways, hope he's back soon. His return will probably determine how our season pans out.