I would think that anything baseball related is fair game here, with a White Sox point of view as the overall focus. I also believe that the Cubs are, in fact, our rivals. So we only play them 6 games per year, but those 6 games are usually the most important games of the year to the average Chicago baseball fan. Note that I said average, not knowledgeable.
You can't deny that if the Cubs sign Madducks that it will have an impact on the Sox in some way.