Offseason
- October 7, 1969: Curt Flood, Byron Browne, Joe Hoerner, and Tim McCarver were traded by the Cardinals to the Philadelphia Phillies for Jerry Johnson, Dick Allen, and Cookie Rojas. Curt Flood refused to report to his new team. The Cardinals sent Willie Montañez to the Phillies on April 8, 1970 and Bob Browning (minors) to the Phillies on August 30, 1970 as compensation.
- January 17, 1970: Mike Tyson was drafted by the Cardinals in the 3rd round of the 1970 Major League Baseball Draft.
- March 31, 1970: Ramón Hernández was released by the Cardinals.
Read more about this topic: 1970 St. Louis Cardinals Season