Home_runs_per_nine_innings
In baseball statistics, 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 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.[1] Pitchers with high fly ball rates are more likely than pitchers with high ground ball rates to have high HR/9 rates.[1]