Going Deep: Perceived Velocity

(Photo by Juan Salas/Icon Sportswire)

Perceived velocity is a term that’s been kicking around for a while and it isn’t exactly clear to the average baseball fan what that means. You can surmise what it pertains to; what speed a pitch appears to be to a hitter. Well, there is a bit more to it than that. Some pitchers are great at it and can use it to their advantage while others rely on different methods to gain an edge. Regardless, perceived velocity is something that should be part of any pitcher analysis/discussion.

First, let’s dive into the 2018 perceived velocity leaders and compare their actual velocity using baseball’s standard pitch, the two or four-seam fastball (as of August 2nd).

So we see a bit of a correlation of success between higher perceived velocity versus actual pitch velocity; mainly involving Zack Wheeler, Jacob deGrom, and Stephen Strasburg. However, this isn’t conclusive because the sample is incredibly small and there is variance in the results of ERA- compared to velocity difference.

So how do we quantify perceived velocity? How can we attribute it as an asset to a pitcher? Let’s take a look at how it works.

EXTENSION 

As mentioned, perceived velocity is as simple as a 95 MPH fastball appearing to come at a hitter, say, two MPH faster than it actually is. How is that even possible? Well, for one, you can take into account extension; the longer you hold your release and the closer to home plate you are, the faster it’s going to appear to come at the hitter. This is one of the reasons why tall, lanky pitchers like Aroldis Chapman can be successful; less time for the hitter to make a decision especially if you throw hard. While fractions of a second might not seem like much, they are important to a hitter who has milliseconds to identify and commit to a pitch. Below is an example of reaction time for a hitter; keep in mind that speed isn’t a factor, time(ing) is.

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So to summarize thus far, the longer you can hold the ball and the further down your release plain is, the harder you make things for a hitter. But, the concept goes a bit further than that.

Simply having a late release is only part of the notion. Remember that a later release/longer extension is tantamount to having the pitching rubber closer; a seven-inch extension versus a five creates an illusion of the pitcher’s mound being (theoretically) two inches closer to home plate; a sizeable advantage. But, that advantage has some caveats.

First and foremost, the following research from Driveline Baseball:

…research shows that a pitching upper arm that is translated closer to home plate with respect to the trunk (shoulder horizontal abduction) is negatively correlated with fastball velocity. (source: Sherwood, Hinrichs, Yamaguchi, 1997)

In layman’s terms, if your mechanics are off, it really doesn’t matter how far your extension is or how hard you throw. Your torso should be rotated in a manner that allows your throwing shoulder to be closer to home plate. Try this- while sitting, reach out for something that’s close to you. Now, still seated, reach for something farther away. Notice how your shoulder starts to move toward the object? That is how the extension can be more effective. Just because a pitcher has longer arms does not mean they are able to use the extension to their advantage without the proper mechanics (torso rotation, shoulder lead).

HIDING THE BALL

While ‘good’ extension is a valuable asset, it won’t matter as much if the pitcher isn’t concealing the ball long enough through his motion. Here is an excellent summarization by Oakland Athletics pitching coach Scott Emerson:

Sometimes it’s, ‘Oh, this guy can spin it,’ and people are wondering ‘Why does he have a 6.00 ERA?’ Well, he has a 6.00 ERA because he doesn’t hang onto his mechanics well enough. He exposes the ball to the hitter sooner. It’s like a boxer bailing out on a punch. If we’re boxing and I open up too much, I’m exposed and you can hit me with a left hook. But if I’m driving through you, I’m not exposing myself. I’m not giving you the opportunity to beat me up.

There is much ado about spin rate, and for good reason; spin does all sorts of things to help a pitcher beat a batter. But, as Emerson mentions, none of that matters if a hitter can see what is being thrown to them. Meaning, you can have an elite spin on your fastball (attributing either horizontal or vertical movement) but if you open your movement too soon (such as opening your front shoulder) the hitter gains a significant advantage. This is not to say they will actually make contact with the ball but they have a much better idea what they’re up against. You can throw the ball as hard as you want, but if you open your body up during delivery, the hitter is going to have a much earlier recognition point giving him those extra milliseconds to either take or commit to the pitch.

I want to preface the following data by telling you these aren’t perfect examples but just visual ideas of what goes into hiding a ball during delivery.

Here is an example of a pitcher hiding the ball well. Fernando Rodney of the Minnesota Twins keeps his body closed and opens right when he’s at or near his release point. Notice how Rodney keeps his shoulder closed until he plants his lead foot and uses torque to turn and release the ball.

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Now an example of a pitcher opening up earlier than he ought to; Bartolo Colon may be of generous proportions but not enough to hide his pitches when he opens his shoulder too soon. Colon opens before his plant foot hits the mound, exposing his pitch to the batter despite the fact that the pitch was taken for a strike.

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I also want to point out that despite the fact that Colon doesn’t appear to hide well, he is an expert at locating his pitches allowing him to live an die by that ability.

That brings us full circle and back to the earlier portion pertaining to perceived velocity leaders. Let’s take a quick gander at deGrom, his mechanics and how they affect his perceived velocity.

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The first pause in the gif is the point at which deGrom plants his foot. Here we can see he is still ‘hiding’ the ball. The next pause is a (nearly) perfect perpendicular release to home plate; I could elaborate further on that but it will lead us off on a tangent that would be better served in a separate article. deGrom demonstrates strong mechanics which is a big reason why he’s able to be successful.

There are other subtleties that I didn’t touch on here, such as how changing eye levels can add or subtract perceived velocity due to the ball being closer or farther from the hitter’s eye. The main idea is hopefully presented here and allows you to take another facet of a pitcher into consideration when evaluating how effective he actually is beyond the numbers.