As you have surely heard, Randy Johnson announced his retirement last night. Matthew took the first look at this, noting that he retires as someone who could be a three-win pitcher next year. Here I am going to take a more backward-facing look. Johnson retires as the career leader in strikeouts per inning, and he did so facing almost entirely right-handed (opposite-handed) batters. In Johnson’s career he faced 14,963 RHBs and just 2,103 LHBs, but over 28% of those RHBs struck out. With the pitchf/x data from the past three years here, we examine how he was able to do this as a small retrospective of his first-ballot Hall of Fame career.
Over the past three years, those covered by the pitchf/x data, Johnson threw, for the most part, just three pitches: a fastball, which Dave Cameron noted has been losing speed for years and in 2009 averaged less than 90 mph; a slider, which in the same article Dave noted has not lost any speed since 2003; and a split-finger fastball, which functions like a changeup. Over the years covered by the pitchf/x data, since 2007, and against RHBs he thew the fastball half the time, the splitter about 18% of the time and the slider 32%. That he can throw his slider, which typically shows an extreme platoon split, that often to RHBs is incredible.
Against RHBs he threw his slider inside and low in the zone, while his splitter was outside and also low in the zone. Not only did he throw his slider to RHBs often, but he did so effectively. Opponents scored 1.4 runs fewer than average per 100 sliders Johnson threw to RHBS, and it got them (RHBs) to miss on 26% of their swings. This is not that far off the average whiff rate of 29%, which is overwhelmingly generated during same-handed at-bats. His splitter also had a 26% whiff rate against RHBs. That gave Johnson two solid pitches against which RHBs had a tough time making contact, and allowed Johnson to pile up strikeouts.
I tip my figurative cap to Randy Johnson and his amazing 22-year career.