ynotjanns, to get pitchers down to 1, you usually need to (temporarily) send them up to the big league roster.
Then go back in the Manager's Center and click on "show defensive ratings" - this will give you the defensive rating and range of that pitcher under the fictional name.
You can then cross-check with the list you already have (a good move is to first either to open a second internet window so you can view both your draft center and your team page, or to save the search you just did for that AAA pitcher so you can go back to it) and you will see which one it is from that list of possible pitchers.