One of the best-known pitching coaches in baseball is stepping aside to tend to family matters.  MLB.com reports longtime St. Louis Cardinals pitching coach Dave Duncan will step down today to be with his wife, who is recuperating from brain surgery in August.  Duncan missed the last several weeks of last year's regular season to be with his wife before returning on the last day of the regular season and throughout the Cards' World Series run.  The longtime right-hand man to Tony La Russa has been with St. Louis since 1996.  Duncan also coached with the Indians, Mariners, White Sox and Athletics and spent 11 major league seasons as a catcher.