As we learned from the Marbury experiment, it takes a long time to get back into playing shape. Even with Marbury, though, he was at least working out on a regular basis. Not too sure about J-Will. Something tells me that he spent most of his time relaxing and enjoying time with his family.
I think we would be better off passing on Williams. Even though I was a huge fan of his, we probably shouldn't take the risk of him not panning out.
I still hope that Marbury decides to come back because it did seem like he was improving in that Orlando series.