I would try to use a magnet and pull the visible end of the fork towards you as far as it will go. Then try to rotate the fork into proper alignment. The only way it could get like this would be for the other end of the fork to have come off the pivot (ball pin, #6). But the ultimate question is did it come off during the slave swap, or did the plastic pivot fail causing all of this?
If I'm envisioning the innards correctly, pulling the slave end of the fork rearward will push the opposite end (pivot end) forward, off the pivot. When you rotate it you will be trying to match up the pivot with its dimple on the fork. The fork has a dimple on the pivot end just like the slave end.
If you can get the pivot end matched up, I'd put forward pressure on the slave end with a Phillips screwdriver or something like that. Ir maybe even your finger. While you are holding forward pressure, try rotating the fork clockwise (like it is now) or counter clockwise. If it still rotates I'd guess the plastic pivot failed.
I hope that all makes sense
