Strikeouts per nine innings

In baseball statistics, strikeouts per nine innings (denoted by SO/9 or K/9) is a measure of the strikeout ability of a pitcher; calculated as the number of strikeouts obtained for every nine innings pitched: (9 x number of strikeouts) / (innings pitched).

The all-time leader in this statistic is active New York Yankees pitcher, Randy Johnson (11.119 SO/9). The only two other players who have averaged over 10 are both active, Kerry Wood (10.432) and Pedro Martinez (10.399).