After spending 2007 pitching in Korea, Bowers signed a minor league contract with the Rockies before the 2008 season. He was called up for the first time in his career on July 1, 2008, and made his major league debut with the Rockies on July 2. He became a free agent at the end of the season and re-signed with the Rockies on January 14, 2009. Bowers was later released by the Rockies and signed a minor league contract with the Philles. On December 14, 2009 he was signed by the Oakland Athletics.