Dwight's shoulder is not going to be normal until after the season with surgery...so rest really won't help much other than soothe lingering pain and discomfort. Once he gets whacked on the arm...and we all know that is how the defenders play him now...the pain will return.
I don't think we will need him against the Pistons. Pau at center should be able to control the paint. I do think we will need Dwight in Brooklyn...so any rest he can get until then would be ideal.