Fix for Sagging Map Pocket?

[kdh454]

My map pockets have a serious sagging problem. I'm sure there is some kind of elastic band in there that is no longer functioning. Is this something that can be replaced easily (no sewing) or am i going to have to take it to someone? The material is in pretty good shape and I'd rather not replace it with some aftermarket junk.

I've yet to pull it apart, just thought I'd post it here first in case anyone has done this before.