John Joseph "Jack" Warner (August 15, 1872 – December 21, 1943) was a professional baseball catcher who played in Major League Baseball from 1895 through 1908. He played for the Boston Beaneaters, Louisville Colonels, New York Giants, Boston Americans, St. Louis Cardinals, Detroit Tigers and Washington Senators. In 1906, Warner was part of the first season-long platoon arrangement in baseball, sharing time at catcher with Fred Payne and Boss Schmidt.