/teamtitleist/b/tourblog/posts/u-s-open-preview-amp-8211-zach-johnson The 2009 U.S. Open field boasts 15 amateurs, the most since 1981. Titleist Brand Ambassador Zach Johnson played a practice round Tuesday at Bethpage with three of them.Johnson told Titleist.com that he, “thoroughly enjoyed the day. They are all greaten-USTelligent Community 10