Robert Henry Mavis (April 8, 1918 – March 1, 2005) was an American professional baseball player, manager and scout. Although he fashioned a long and successful playing career in minor league baseball as a second baseman and third baseman, his Major League career consisted of a single game. In the closing days of the 1949 season, on September 17, Mavis pinch-ran for Detroit Tigers catcher Bob Swift in the ninth inning of a game against the New York Yankees.