Berkshirebub,
Welcome to the Berkshire Forum.
I'm not sure what kind of slide you have, but if it is a Schwintek, you are in a well-discussed area of problems and solutions. My discussion at
https://www.forestriverforums.com/fo...de-175612.html has been read more than 10,000 times, for example.
Schwintek slides (and other brands, I am sure) have rollers on the coach wall and the whole slide runs on these rollers. Heavy slides, like kitchen slides, can dig into these rollers if they have an underside made of wood. So, many of us have installed 1/8" aluminum plates to make the slide roll better. That is typically motivated by a poorly functioning slide.
So, this could be the source of your slide scraping on the floor. I have the same problem and the repairs to my kitchen slide didn't completely eliminate that problem. What I do is place a 1/8" piece of plexiglass on the floor where the slide scrapes and hold my foot on it while the slide closes. (Actually, my wife is the one who usually does this, so she deserves credit!)
If you put a roller under the fridge, it could stop the floor from being scraped, but cause other problems. For example, if you have a ceramic tile floor, the roller might crack the tiles and you will have a bigger mess. Thus, you should give serious consideration to the plexiglass solution. I store the plexiglass under the seat cushion in the dinette.
–Gordon