The Colorado Rockies are a Major League Baseballfranchise based in Denver, Colorado. Formed in 1993, they play in the National League West division. Pitchers for the Rockies have thrown 1 no-hitter in franchise history, which was accomplished by Ubaldo Jiménez on April 17, 2010. A no-hitter is officially recognized by Major League Baseball only "when a pitcher (or pitchers) retires each batter on the opposing team during the entire course of a game, which consists of at least nine innings". 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. A no-hitter is rare enough that only one team in Major League Baseball has never had a pitcher accomplish the feat.[a]
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." 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." These calls define every baseball game and are therefore integral to the completion of any no-hitter.
No perfect games, a special subcategory of no-hitter, have been thrown in Rockies history. As defined by Major League Baseball, "in a perfect game, no batter reaches any base during the course of the game."