Taking a Closer Look: The Slider

It was recently brought to my attention that there has been an emerging trend among pitchers in Major League Baseball to rely less on their fastballs and more heavily on their secondary/off-speed pitches. With this in mind, let’s take a look at a few charts I put together displaying this trend starting from the 2002 season all the way through the 2014 season.

All data was retrieved from FanGraphs.



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As one can see, the first chart illustrates the decrease in the percentage of fastballs thrown by pitchers. The decrease has been fairly constant falling from 64.4% in 2002 to 57.7% in 2014. Having said that, the average velocity of fastballs has increased, as illustrated by the chart below.


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The average velocity of a fastball has increased by nearly 2 MPH since the 2002 season, when the average fastball velocity sat at 89.9 MPH. Although the average speed of fastballs has increased over the years, pitchers have seemingly decided to rely less on their fastball and more on their off-speed pitches. The next chart will show how often pitchers throw sliders.


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The slider might very well be the most effective pitch in the game of baseball. In 2002 and 2003, sliders were thrown about 12% of the time. As time progressed, in part due to pitchers throwing less fastballs, the slider was relied on more heavily, reaching a peak of 15.6% usage in 2008. Since then, it appears that the slider has typically been used a little over 14% of the time. Moreover, the average velocity of a slider has increased nearly 2 MPH since the 2002 season. The slider is the most used off-speed pitch in baseball, and according to FanGraphs “Pitch Value”, the slider is also the most effective pitch in the game of baseball. Pitchers have appeared to pick up on the fact that hitters are having tremendous difficulty with this pitch as the usage of sliders has seen an increase over the years.

It should be noted that this recent trend has generally occurred thanks to relief pitchers. Last season, starting pitchers threw sliders 11.9% of the time, while relief pitchers threw sliders 17.3% of the time. The average velocity of sliders for starting pitchers and relief pitchers were fairly similar in 2014. Relief pitchers have the ability to dial it up over a compressed number of pitches, and can often pitch only for the strikeout. Starting pitchers typically have to dial it back and attempt to generate contact early in the count.

One might wonder if starting pitchers could be even more effective if they threw their slider more often, as it appears to be an incredibly successful pitch. In 2014, starting pitchers who relied heavily on their slider include the likes of Tyson Ross (41.2%), Madison Bumgarner (35.0%), Francisco Liriano (31.8%), Clayton Kershaw (29.4%), and Chris Archer (28.9%). Not a bad list of names, and those are just a few of them.

It is a lot easier said then done, but if you’re a pitcher, taking the time to master the slider might not be such a bad idea. In fact, it might help the pitcher take the next step from good to elite. The most dominant pitchers in the entire game of baseball have seemed to truly master the art of throwing a slider. Nonetheless, these are the best hitters the world has to offer, so they could, and probably will, make adjustments and learn how to handle the slider at a more effective level. Until then, keep on throwing the slider because it will produce outs. And lots of them.

One Response

  1. Slider Domination

    Great Article! The new trend in pitch breakdown shows that pitchers are relying more on movement to get hitters out. With an increase in the percentage of Sliders being thrown, this makes their PLUS+ Fastball velocity even more difficult for hitters to time.


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