The Slider That Won’t Age

When we tell our kids about Randy Johnson, we’re going to start with the height, the hair, and the velocity. In his prime, he regularly threw 100 MPH fastballs with varying amounts of command, making him one of the most intimidating pitchers in the history of the game. At 46, he’s seen his fastball desert him, as the guy who used to throw harder than anyone else now has a fastball that averages below 90 MPH. Here’s a look at how his fastball velocity has decreased since 2002.


There’s a couple of precipitous drops in there, as he’s lost 5 MPH off of his heater in the last eight years. As he’s battled injuries the last few years, the decline has become rapid. Time has caught up with the Big Unit, and his fastball is now a below average pitch.

However, Johnson’s still racking up the strikeouts, because the fastball has never been his out pitch. His slider has been the one that he’s leaned on when he wants to put a hitter away, snapping off a nasty breaking ball that eats lefties alive and even gives problems to right-handed hitters. For whatever reason, that slider just refuses to age.


He lost velocity on it from 2002 to 2003, but since then, it’s been constant at around 84.5 MPH. Even as age has eaten away at his fastball, the slider has held its ground, and could still be described as a power breaking ball. And it’s that pitch that allows him to still put hitters away when he needs to.

Johnson may choose to hang up his spikes and walk away. As a 46-year-old free agent with a long line of health problems, he’s got some incentives to retire. But if he decides to come back for one more year, he’s still got a major league out pitch. For reasons that I certainly can’t explain, his slider just refuses to age as his fastball has.

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Dave is the Managing Editor of FanGraphs.

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I think even if he doesn’t have the stamina to start anymore, his slider makes him a superstar LOOGY or all star reliever.