If Craze left then a local player would more than likely back up Murphy, He would only ever get ice time if Giants were 10 up so hardly worth bringing in an import back up.
If Murphy was to get injured the Giants would then bring in import cover and deregister a player for the length of time Murphy was out.
I believe it's something to do with Doug, he may have got offered a another job in the real world so to speak, would be very very surprised if he went back to the Caps with getting so close to silverware last year.