Tom - I'm actually not sure it has been covered before.
In any case, just guessing, but I think it's owned by a homeowner nearby and is his personal practice area. Either that or it's short-game practice area for the members. It can't possibly have any role in the golf course - as you can see from the aerial, it's surrounded by trees... and what the aerial doesn't show you is that the trees are enormous and thick and separate this little green from the rest of #18 completely.
TH