Sliding patio door rollers

Hello! Thanks for reaching out to us. We may be able to supply you with a matching roller, but your photos here only show the internal portion of an assembly. That's not enough to go by, unfortunately.

There should be an external housing still in the door. I'll have to see the whole assembly put together in order to make a recommendation. Would that be possible?

What you're showing here is the internal housing. Rollers like yours require two housing components as a rule: internal and external. Without that setup the roller would not be able to adjust, and therefore not function properly. Patio doors like yours very, very rarely use single housing setups.

I am very confident that the part you're showing here is just the internal component. If there is no external housing, and it is just screwed to the door as you describe, then someone must have taken an assembly apart to do a very sloppy repair. 

Either way, internal components like this are not sold separately and without seeing the whole assembly it's not possible to ID. I highly recommend checking your door again, just to be safe. Otherwise, we will not be able to assist you with this project.