Team Logo. The Arizona Diamondbacks are a team in Major League Baseball. They play in the National League. They are the fastest expansion team in the majors to win a championship. Retrieved from "https://prosportsteams.fandom.com/wiki/Arizona_Diamondbacks?oldid=16184" Categories: Major League Baseball teams National League teams NL West teams Teams in Arizona Teams in Phoenix Add category Cancel Save Community content is available under CC-BY-SA unless otherwise noted.