Offseason
- November 28, 1989: Bryn Smith was signed as a free agent by the Cardinals.
- November 30, 1989: Danny Cox was signed as a free agent by the Cardinals.
- December 6, 1989: Jim Lindeman and Matt Kinzer were traded by the Cardinals to the Detroit Tigers for Bill Henderson (minors), Marcos Betances (minors), and Pat Austin (minors).
- February 27, 1990: Alex Cole and Steve Peters were traded by the Cardinals to the San Diego Padres for Omar Olivares.
Read more about this topic: 1990 St. Louis Cardinals Season