Ed, the roller maybe off its bracket mounting and needs a nut attached.
Here is a thread
on how to lift the slide with help and using 2x4's to get the space required.
In General slide info on page 4 they show how to lift if replacing a rug but with help you should be able to get the blocks under slide with it out about 1/2 way.
Make sure you get a long 2x4 under the whole slide floor and not just the edge of slide floor.
While we are at it here's one for rear slide