Pitchers for the Astros have thrown seventeen no-hitters in franchise history, the most of all of MLB's expansion teams added since 1961.
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".
They no-hit the Cincinnati Reds, the Los Angeles Dodgers, the New York Yankees, the Philadelphia Phillies, and the Toronto Blue Jays the most, which occurred twice.
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.”[4] 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.
The tasks of the manager include determining the starting rotation as well as batting order and defensive lineup every game.