Indeed, we don't know. But if it's because Norwich want him, I think it's particularly dumb to just sack him. If it's because they've got Zola, I think it's particularly dumb for different reasons.
At the moment, my money is on dumb.
Colin went because he had an offer he wanted - that's life (we got compensation). And the backroom staff could all go to Norwich if Rowett went there, but until then why wouldn't they carry on doing their job?
If that was the case:
a) let Norwich pay for him
b) keep the backroom staff for a while so that the team can play properly until a new manager comes in. Possibly just suspend the manager for doing something wrong, get the team to feel they've been ditched and they need to prove their exiting...