What would someone in that role do though? I don't like the idea of them bringing the players in as surely the manager should do that as it's his system?
In an ideal world the DoF is in continuous discussion with the head coach about transfer targets. Once they have a list, a good DoF does the donkey work of chasing them up, monitoring their availability, talking to agents and so on. He also organizes the scouting and deals with the contracts of the players already at the club.