The Arizona Diamondbacks are a Major League Baseball (MLB) franchise based in Phoenix, Arizona. They play in the National League West division. The first game of the new baseball season for a team is played on Opening Day, and being named the Opening Day starter is an honor, which is often given to the player who is expected to lead the pitching staff that season, though there are various strategic reasons why a team's best pitcher might not start on Opening Day. The Diamondbacks have used six different Opening Daystarting pitchers in their 15 seasons. The six starters have a combined Opening Day record of six wins, four losses (6–4), and five no decisions. No decisions are only awarded to the starting pitcher if the game is won or lost after the starting pitcher has left the game.
Randy Johnson holds the Diamondbacks' record for most Opening Day starts with six, and has an Opening Day record of 3–2. Brandon Webb started four Opening Days, and Ian Kennedy has been the Opening Day starter twice.Andy Benes, Javier Vázquez, and Dan Haren have started one Opening Day each. Webb, Haren, and Kennedy habe the best winning percentage as the Opening Day starting pitcher with a record of 1–0 (Webb has three no decisions and Kennedy has one no decision). Benes and Vázquez are tied for the worst Opening Day record, both at 0–1. Webb is Arizona's only pitcher with multiple no-decisions on Opening Day (three), and Johnson is the only pitcher to have won two or more opening games.