William Francis Carrigan, nicknamed "Rough", was an American Major League baseball catcher and manager. He played for the Boston Red Sox between 1906 and 1916, and he was a player-manager for the last four of those seasons. In 1915 and 1916, Carrigan's teams won back-to-back World Series. He was said to exert a positive influence on young Red Sox star Babe Ruth, serving as his roommate and his manager. He has the highest postseason winning percentage (.800) of any manager with multiple postseason appearances, and was named to the Honor Rolls of Baseball in 1946.

The 1915 World Series was the championship series in Major League Baseball for the 1915 season. The 12th edition of the World Series, it matched the American League champion Boston Red Sox against the National League champion Philadelphia Phillies. The Red Sox won the Series four games to one. It was the last World Series to start on a Friday until the 2022 World Series.