It appears (not yet verified) that one or more of the (plastic) rollers under the refrigerator may have disintegrated (or, be in the process of doing so).
[I suspect the "webbing" inside the roller has fractured based on the bits of plastic I've discovered under the unit]I'm thinking of strapping it to my "refrigerator dolly" and leaning it back "for transport" to expose the underside. By carefully choosing the side from which to approach the refrigerator, I should be able to MOST elevate the rollers in question. Not the greatest in terms of accessibility but should be enough to expose the rollers and any mounting hardware necessary to remove/replace.
I can't imagine any OTHER way to get at the underside of the unit? And, I'm sure we're not the only ones who will have had to replace these rollers (given that they are a replaceable "spare"!)
[Note to self: remove liquids from refrigerator before doing so]