Dellos Clinton Gainer (November 10, 1886 – January 29, 1947), nicknamed "Sheriff," was an American baseball player. A native of West Virginia, Gainer played professional baseball, primarily as a first baseman, for 21 years from 1909 to 1929, including 10 seasons in Major League Baseball for the Detroit Tigers (1909, 1911-1914), Boston Red Sox (1914-1917, 1919), and St. Louis Cardinals (1922). In his first full year in the major leagues, he drew praise for his fielding and was batting .302 when he was struck by a pitched ball and sustained a broken wrist. Gainer suffered from the wrist injury and other injuries over the next several seasons.