[talkSAFT]

Over the park we used to have Running-goalies if there was (say) 5 against 6.
I can see Ben Foster in that role if we get a player sent off. One of the Linesmen could cover the goal when Ben gets up the field.

We use to call them Rush Back Goalkeepers. but I suppose it evolved a little a couple of decades on from you saft  

I've got this (black & white) picture of our Beefy "rushing back", red-faced, his big gut swaying side-to-side, before collapsing on one of the 'goalposts'.