He isn't he's playing as the most advanced midfielder, as did Saville for a lot of last season, but whatever position he's playing is down to the manager who himself said when before the Plymouth game 'George (Saville) going back to Millwall has allowed us to bring Matthew (Crooks) in, he's someone I've liked for a while and he's a wholehearted player who offers us more options in the middle of the park' to me it seems like Warnock sees Crooks as Saville's replacement.
The other option is that Warnock has decided to play a different way with different personnel, in which case you yourself are opining that we should have stuck to the system of last season rather than change and, again, those decision's are down to the men with initials on their tops of which Warnock is the most senior.