Outside the literary world, Plimpton was famous for competing in professional sporting events and then recording the experience from the point of view of an amateur. In 1958, prior to a post-season exhibition game at Yankee Stadium between teams managed by Willie Mays (National League) and Mickey Mantle (American League), Plimpton pitched against the National League. His experience was captured in the book "Out of My League". (He intended to face both line-ups, but tired badly and was relieved by Ralph Houk.) Plimpton sparred for three rounds with boxing greats Archie Moore and Sugar Ray Robinson while on assignment for "Sports Illustrated".