The Arizona Diamondbacks are a Major League Baseball franchise based in Phoenix, Arizona. Formed in 1998, they play in the National League West division. Pitchers for the Diamondbacks have thrown 3 no-hitters in franchise history.^[1] A no-hitter is officially recognized by Major League Baseball only "when a pitcher (or pitchers) allows no hits during the entire course of a game, which consists of at least nine innings", though one or more batters "may reach base via a walk, an error, a hit by pitch, a passed ball or wild pitch on strike three, or catcher's interference".^[2] No-hitters of less than nine complete innings were previously recognized by the league as official; however, several rule alterations in 1991 changed the rule to its current form.^[3] Randy Johnson threw the first and only perfect game, a special subcategory of no-hitter, in Diamondbacks history on May 18, 2004.^[4] As defined by Major League Baseball, "in a perfect game, no batter reaches any base during the course of the game."^[2]

The umpire is also an integral part of any no-hitter. The task of the umpire in a baseball game is to make any decision "which involves judgment, such as, but not limited to, whether a batted ball is fair or foul, whether a pitch is a strike or a ball, or whether a runner is safe or out… [the umpire's judgment on such matters] is final."^[5] Part of the duties of the umpire making calls at home plate includes defining the strike zone, which "is defined as that area over homeplate (sic) the upper limit of which is a horizontal line at the midpoint between the top of the shoulders and the top of the uniform pants, and the lower level is a line at the hollow beneath the kneecap."^[5] These calls define every baseball game and are therefore integral to the completion of any no-hitter.^[6]

The manager is another integral part of any no-hitter. The tasks of the manager include determining the starting rotation as well as batting order and defensive lineup every game.