Kos and Ozil have hardly had a rest though since August last year, pretty much every PL and CL match i think. Giroud broke his ankle or something and was out for 2/3 months. It could be the reason they've been allowed an extended rest. I don't know obviously, but it could be the reason
As Redknapp said on Sky, give them a rest in a few weeks once your injury situation has cleared up. Particularly Kos, given the problems they had at CB it was mad to not select him.