In a cricket match , there are total 11 players which we called as playing eleven who will be there fielding and batting for a side.
There are different positions on which the fielders can be placed such as a gully,slip,third man etc.
In a standard cricket match we can remove fielder from slip and put him at the gully or anywhere else we want(of course within and according the ICC rules for fielding positions).
My question is can we remove a wicket keeper from his position leaving his field blank(no one behind the stumps) and make him field at the slip?
Is it required to have a wicket keeper behind the stumps every time?
Is there any rule?