Can't understand anyone expecting Riis to start. It isn't an AN thing I don't think there are many modern managers who would play him in the circumstances. It isn't even about him learning the system it's about him having a bare minimum understanding with his team mates, he couldn't train with the squad on Friday so he won't have even passed the ball to any of his new teammates yet. Another post has said all he needs to do is hold the ball up and lay it off to his teammates, that's heavily dependent on him knowing what runs they're likely to make.
This isn't Sunday League football and whilst he doesn't need weeks and weeks to learn the system he at least needs to have had a kick about with his teammates before starting a league game with them. If you disagree fair enough but it can't be used as a stick to beat AN with when the vast majority of other managers would do the same.