Going Deep: Effective Velocity and Reaction Time

Michael Augustine discusses effective velocity and its relation to hitter perception.

(Photo by Tim Spyers/Icon Sportswire)

A little less than two weeks ago I wrote an article about perceived velocity, simplifying the concept best I could. I discussed pitching mechanics and how hiding the ball can actually make a pitch appear to come faster than it actually is (arm extension also plays a factor). Today I’m going to take it one step further and explore what is known as effective velocity and how it affects hitters timing/perception.

You could consider perceived velocity and effective velocity essentially the same thing. However, I feel there are a couple of things that differentiate the two terms despite the fact they can be interchangeable. The first is in the word ‘effective’. ‘Perceived’ alludes to what the hitter sees and is working with. Effective tends to relate to the individual using the ‘tool’; the pitcher. So, from here on out, I’ll be using ‘effective velocity’ in the context of how it benefits a pitcher and causes a hitter to have to adjust to a located pitch.

What makes a pitch effective? Location? Speed? Selection?

The first thing I’m going to look at is the strike zone. It can be broken up into 9 different quadrants when applying sabermetric concepts; batting average in each location, exit velocity, average pitch speed, etc. We see everything in the form of a four-sided object. When talking effective velocity, we have the same four-sided zone but with two sections; up and in along with down and away, divided by two triangles. The strike zone gets separated diagonally starting from the top, inside corner of the strike zone on the hitter’s side (don’t worry, there will be a graphic in a minute).

So what do these two triangles exemplify? Simply put, from about the middle of the zone to a 45degree angle up to the top corner of the respective batter side zone is where a pitcher can achieve (perceived) elevated velocity. Now, that’s not to say that a pitcher is guaranteed success pitching in this location; it helps (and I’ll explain why) but its certainly not a given. There is also a way to take advantage of the flip-side of this zone (lowered perceived velocity), both of which I’ll address momentarily.

In general, here’s how it works. A pitcher throws a 95 MPH fastball up and in. The pitching gun may read 95 but to the hitter, he perceives the pitch to be coming in as fast as 99 MPH. How, you might ask? Well, it’s complicated, but essentially the hitter has less time to react to a pitch coming at him from that angle as opposed to other lower and/or away pitches. The batter must adjust his swing speed by reacting faster. While the pitch is still 95 MPH, the hitter has to react as if he’s getting a 99 MPH fastball.

Here is a video that can get into the nuts and bolts of effective velocity, authored by whom many consider to be the pioneer of this concept, Perry Husband.

On the opposite side, of course, the reverse is true. It’s not detrimental to the pitch but rather can induce timing issues for a hitter. The batter might be waiting on a 95MPH fastball, get a 95MPH fastball but swing too early because the location (down and away) makes for a pitch that appears to be slower due to the proximity of the ball to the hitter.

Confused? That’s OK. Here is a graphic to help make a little more sense.

(via MLB Network)

This view is taken from the perspective of a left-handed hitter. Pitches in the red portion of the zone can gain as much as three (sometimes four) MPH depending on how close to the upper quadrant of the zone the location is. The blue shows how a pitch can be perceived to lose velocity the farther away from the hitter it is located. Again, this isn’t exactly a foolproof plan. It’s more to disrupt the timing of the hitter by being able to locate a pitch under the same velocity in a different portion of the zone based on the handedness of the batter.

Let’s look at some visual examples featuring Cincinnati Reds pitcher Tyler Mahle. I use Mahle because he has the highest percentage of up and in fastballs (15.2%) of any qualifying pitcher to left-handed hitters. I picked lefties for no reason other than the graphic above is from a left-handed hitters perspective.

Keep in mind my assertations of this at-bat are strictly speculation based upon the concepts I’m applying. The red sections represent lowered (perceived) velocity and the green heightened velocity.

Here is pitch number one of the at-bat versus Odubel Herrera. Mahle starts off throwing a 93MPH fastball down and away.


We know from my earlier statements that down and away can appear to take off as much as 3-4 MPH on a pitch. Mahle threw 93 but Herrera’s eyes see roughly 89/90MPH.

Pitch number two has Mahle returning to low and away with a 92MPH fastball.


Again, Herrera’s eyes are telling his brain that he’s actually seeing 88/89 MPH.

Once more Mahle attacks down and away with a 93 MPH fastball, this time for a ball. Mahle seems to be trying to set Herrera up for something.


On pitch number five, Mahle starts his strikeout attack by changing eye-level and taking advantage of effective velocity. Up until this point, Herrera is likely expecting 90-ish MPH fastballs.


Herrera swings late probably because he was anticipating the pitch to come in slower; perceiving a 93 MPH fastball to be more like 97 MPH, and ends up fouling off the pitch.

Now on pitch six, we see the same thing; up and in drawing another foul on a late swing. He’s a bit more on time but his swing but still can’t extend his arms and actually swings slightly under the pitch.


This matchup ended with Herrera hitting a slider for an infield single on pitch seven of the at-bat. Again, changing eye-levels and taking advantage of effective velocity doesn’t guarantee success; Herrera swung at a bad pitch and got lucky. Below is a visual depiction of all pitches thrown to Herrera during this at-bat; all fastballs with the exception of the slider (yellow).

So effective velocity can work by increasing as well as decreasing the speed of a pitch strictly in terms of hitter cognizance. It’s a very useful tool for pitchers, especially in the age of launch angle, where hitters are swinging at more of an upward angle (another discussion for another article). This new-age hitting strategy facilitates more high pitches (fastballs), more popups/flyballs, and allows a pitcher to not only change eye level but throw off a hitter’s timing.

Again, I give a lot of credit and thanks for this article to the aforementioned Perry Husband.

Michael Augustine

Going Deep manager for Pitcher List and a contributor to SB Nation's Royals Review and Gaslamp Ball. I've assisted with the roster and scouting development for Out of the Park Baseball since 2016. You can find my pitching 'art' on gfycat (@Augustine_MLB).

2 responses to “Going Deep: Effective Velocity and Reaction Time”

  1. Perry says:

    Very good piece…………. and I appreciate you referencing my work, that’s a refreshing change.

    If I may, while ‘Perceived Velocity’ is somewhat relative to ‘Effective Velocity’ (Ev), they are very different. First, we can’t say what the perceived velocity of a given pitch is until after the pitch is swung at and even then, only if we know how to measure how early or late the hitter is to 100/100 (100% on time with 100% efficient swing mechanics or the hitter’s ‘A Swing’). When pitchers use Ev Tunnels efficiently, hitters’ perceived velocity is almost always wrong, due to the fact that ‘Ev Efficient Tunnel Pitches’ appear to be heading to an expected location at an expected speed, but never arrive when/where the hitter expects. For example, Scherzer’s FB up/in to a RHB at 96 MPH starts middle of the zone or even outer third and movement takes in closer to the hitter. The perception of the initial flight was a middle fastball at 96 MPH or even a FB away at 93 MPH, but it was really inside at 99 EvMPH or even higher; a 3-6 EvMPH lie. Scherzer’s slider down and away at 87 MPH also starts middle, giving a perception of 96 MPH but was really 84 EvMPH; a 10-12 EvMPH lie. Both pitches would most likely be perceived incorrectly as a middle or away FB, especially since every hitter ever interviewed says they are on when going the other way. So while the perception is part of the overall ‘lie’, the true metric is MPH + or – Location (including movement) = Ev or true reactionary speed needed to ‘do damage’, not simply to hit the ball. That last statement is perhaps the biggest oversight of the understanding of Ev. The Ev Tunnel creates illusions that the hitter uses to perceive speed/location. This is why the Twitter overlays almost always show hitters very early and very late to combos such as described. 15 EvMPH differentials out of the same Ev Tunnel are simply not hit hard very often. Carlos Pena presented my predictions prior to the 2017 Postseason on MLB Now that I did using the Ev Microscope. We were within just a couple of percentage points of all 4 categories of hard contact type. As predicted, only 10% of all hard contact in the PS happened on Ev Efficient sequences, meaning 90% was poor pitching strategy…………..

    Thanks again,

  2. Michael Augustine says:

    OK, that makes a bit more sense. I didn’t look at it as a trajectory concept (tunnels) but more as a location concept; that’s where I’ve made a mistake.
    The Pena Ev clip on MLB Now (the +3/-3 graphic was taken from that) was what led me to your work and inspired me. Hopefully, I did it some justice but I still have some learning to do.

    Thanks for the feedback!

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