The Otamendi move smacked of opportunism, Valencia needed cash and owed us a fair bit, they offered us a player we liked. The problem was Demichelis was suppose to leave but didn't so we took the next best option which was to loan out Denayer to get experience.
I don't think anyone at City expected Demichelis to decline as fast as he has and for Kompany to have his worst season injury wise since his arrival. Coupled with a few injuries for Mangala we were lucky that Otamendi signed.
I not sure if City made the right call but if Otamendi had gone elsewhere and we were left with Demichelis, Mangala, Kompany and Denayer, by the injury records of those 4 this season, Demichelis and Sagna would probably have started an awful lot of matches as our centre backs.