That is the spacer that goes on the end of your oil pick-up tube.
One end of the tube bolts to your oil pump, the other end (by pick-up screen) is supported by that spacer. The end with the bolt molded into it is threaded inside and screws onto a main bearing cap stud.
I'm fairly certain that there's a nut for the other end of that spacer that the bracket on the pick-up tube is secured with. Did you find a small nut too? If not I'd look for one.
Notice that bracket on the oil tube ... that's where it goes.