Sliding door roller worn out or something else??

Hey there,
I have an issue with my sliding door. Just before if closes, there seems to be to much clearance in the inward and outward direction, which causes the contacts sometimes to not align properly. I have looked at the bottom roller, which should be responsible for the guidance in this direction and the roller has a strange recess, see pictures. It looks like it's machined but would allow for a larger clearance. Can anybody confirm whether this roller has a recess, when new or whether this is just worn in so neat, that it looks like it is supposed to be like that.
Thanks

Difficult to see when it's on the van, but mine looks stepless from what I could see.

Yours looks like it's missing something that clips onto that bearing. Couldn't find any help in the diagram:
http://jp-carparts.com/toyota/partlist.php?maker=toyota&type=711140&cartype=136&fig=6758

Thanks for trying. From that link i learn it is only a couple of dollars, so I might just buy it.
Cheers