The Oakland Athletics started their day in a makeshift clubhouse classroom, among the first major league clubs to undergo mandatory domestic violence training. Designated hitter Billy Butler is in favor of baseball's proactive approach on the issue. ''If it helps one guy in here, it's done its job.'' The classes are being taught in English and Spanish through San Francisco-based Futures Without Violence, which works to prevent domestic and sexual violence and child abuse. ''We're very proud to have been selected by both Major League Baseball and the Major League Baseball Players Association to develop a comprehensive strategy to educate and engage players in positive solutions to prevent and end domestic violence, sexual assault and child abuse,'' said Esta Soler, the organization's president.