sliding glass door roller

It's tough to say for sure. At first glance, this looks like our 81-278 or 81-279, but I notice your housing dips down at the front. We have the 81-277, but this has flanges on either side near the rear that increase its width. The  81-004, which is also similar, has bumps that do the same.

All in all, I couldn't find an exact match for this. Look over the four parts mentioned and see if you could adapt any of these to work in your door.