We will definitely need photos in order to help you identify a match. You can upload them right here to this thread for me to review. Please note that we have to see the roller removed from the door in order to get a good look at it. If it's still installed in your photos, then we can't help.
In the meantime, you can see our full selection of screen door rollers here.
I'm afraid I don't recognize this style. it looks like it's just a portion of a larger assembly, though. There is likely still a part of the housing in the door. Would it be possible to see the whole thing?