baseball statistics Baseball statistics play an important role in evaluating the progress of a player or team. Since the flow of a baseball game has natural breaks to it, and normally players act individually rather than performing in clusters, the sport lends itsel ...

, home runs allowed per 9 innings pitched (HR/9IP or HR/9) or home runs allowed per nine innings (denoted by HR/9) is the average number of home runs given up by a

pitcher In baseball, the pitcher is the player who throws ("pitches") the baseball from the pitcher's mound toward the catcher to begin each play, with the goal of retiring a batter, who attempts to either make contact with the pitched ball or draw ...

per nine innings pitched. It is determined by multiplying the number of home runs allowed by nine and dividing by the number of innings pitched.What is a Home Runs Per Nine Innings (HR/9)? , Glossary , MLB.com
/ref> Pitchers with high fly ball rates are more likely than pitchers with high

ground ball In the sports of baseball and softball, a batted ball is a pitch that has been contacted by the batter's bat. Batted balls are either fair or foul, and can be characterized as a fly ball, pop-up, line drive, or ground ball. In baseball, a fou ...

rates to have high HR/9 rates.

Leaders

The career leaders in HR/9IP through 2018 were

Jim Devlin James Alexander Devlin (June 6, 1849 – October 10, 1883) was an American Major League Baseball player who played mainly as a first baseman early in his career, then as a pitcher in the latter part. He played for three teams during his five ...

(0.0448),

Al Spalding Albert Goodwill Spalding (September 2, 1849 – September 9, 1915) was an American pitcher, manager, and executive in the early years of professional baseball, and the co-founder of A.G. Spalding sporting goods company. He was born and raised ...

(0.0468), and

Reb Russell Ewell Albert "Reb" Russell (March 12, 1889 – September 30, 1973) was an American Major League Baseball player for the Chicago White Sox and the Pittsburgh Pirates. Career MLB Russell was drafted by the White Sox as a pitcher in 1912. In his ...

(0.0488). There were 87 single-season leaders in HR/9IP through 2018 who had pitched a season without giving up a home run.Single-Season Leaders & Records for Home Runs per 9 IP , Baseball-Reference.com
/ref> All played prior to 1927. The active leaders in HR/9IP through 2018 were

Clayton Kershaw Clayton Edward Kershaw (born March 19, 1988) is an American professional baseball pitcher for the Los Angeles Dodgers of Major League Baseball (MLB) . He has played for the Dodgers for the entirety of his MLB career. A left-handed starting pi ...

(0.6225),

Adam Wainwright Adam Parrish Wainwright (born August 30, 1981), nicknamed "Waino" and "Uncle Charlie", is an American professional baseball pitcher for the St. Louis Cardinals of Major League Baseball (MLB). The Atlanta Braves selected him 29th overall in th ...

(0.6755), and Charlie Morton (0.7682).Active Leaders & Records for Home Runs per 9 IP , Baseball-Reference.com
/ref>

References

Pitching statistics {{baseball-stub