 Pitchers with high fly ball rates are more likely than pitchers with high ground ball rates to have high HR/9 rates.The career leaders in HR/9IP through 2018 were Jim Devlin (0.0448), Al Spalding (0.0468), and Reb Russell (0.0488).There were 87 single-season leaders in HR/9IP through 2018 who had pitched a season without giving up a home run.