Four-Man Rotation (1939)

“Boss Bill Terry, of the Giants, announced a four-man pitching rotation roster today and the names of Carl Hubbell and Clyde Castleman were missing.” International News Service, “Terry Picks Four Hurlers,” Lexington (KY) Leader, April 4, 1939, p4 (Also appeared in other papers)

No earliest use given in 2009 Dickson Baseball Dictionary