Offseason
- October 15, 1956: Bob Cerv was purchased by the Athletics from the New York Yankees.
- February 19, 1957: Art Ditmar, Bobby Shantz, Jack McMahan, Wayne Belardi and players to be named later were traded by the Athletics to the New York Yankees for Irv Noren, Milt Graff, Mickey McDermott, Tom Morgan, Rip Coleman, Billy Hunter and a player to be named later. The Yankees completed their part of the deal by sending Jack Urban to the Athletics on April 5. The Athletics completed the deal by sending Curt Roberts to the Yankees on April 4 and Clete Boyer to the Yankees on June 4.
- Prior to 1957 season: Lou Klimchock was signed as an amateur free agent by the Athletics.
Read more about this topic: 1957 Kansas City Athletics Season