A World Series of genealogical discoveries. I’m a singer by name and by trade. I am neither a sports fan nor an expert on the subject. But this summer, after seeing the Associated Press report that “no practicing Orthodox Jewish player has made it to the big leagues,” I challenged sports journalists to recognize the most observant Orthodox Jew to have played and won the World Series, Morrie Arnovich. I never imagined the article about my hometown heroes from Superior, Wis., would have led me to discover Morrie was also my blood relative. I didn’t know why I cared so...