The 2018 Arizona Diamondbacks season was the franchise's 20th season in Major League Baseball and their 20th season at Chase Field in Phoenix, Arizona as members of the National League West Division. They were managed by Torey Lovullo in his second season with the Diamondbacks. The Diamondbacks began the regular season on March 29 against the Colorado Rockies and finished the season on September 30 against the San Diego Padres. The D-backs were in first place in the NL West on April 1, May 1, July 1, August 1 and September 1, but missed the playoffs after a September collapse.