N'afọ 1900, Clarke sonyeere Pittsburgh Pirates dị ka onye ọkpụkpọ na onye njikwa, ọrụ ọ ga-anabata ruo mgbe ọ lara ezumike nká na 1915. bụ ihe a na-arụ ụka na ọ bụ oge kachasị mma nke ọrụ Clarke ka ọ na-eduzi Major Leagues na slugging nkezi na OPS ma na-eduzi Njikọ Mba na okpukpu abụọ. O mechara bụrụ onye nke abụọ n'azụ onye otu ya, Honus Wagner, maka aha ịkụ ọkpọ nke National League. Na World Series mbụ
, Clarke gbara.265 mana Boston's Cy Young na Bill Dinneen karịrị Pittsburgh n'ozuzu ma merie usoro ahụ na egwuregwu asatọ.