Offseason
- December 15, 2002: Erubiel Durazo was traded by the Diamondbacks to the Oakland Athletics as part of a 4-team trade. The Cincinnati Reds sent Elmer Dessens and cash to the Diamondbacks. The Toronto Blue Jays sent Felipe López to the Reds. The Athletics sent a player to be named later to the Blue Jays. The Athletics completed the deal by sending Jason Arnold (minors) to the Blue Jays on December 16.
- January 30, 2003: Ricky Bottalico was signed as a free agent by the Diamondbacks.
- February 14, 2003: Scott Service was signed as a free agent by the Diamondbacks.
Read more about this topic: 2003 Arizona Diamondbacks Season