• Demetre Kokoris

New Measurements Applied to Traditional Terms

Updated: Jan 6

In this weeks article Demetre Kokoris dives into how the technological revolution occurring in baseball today isn't all that different from what's been done for years.

It might appear a Civil War has broken out in the game of baseball. Old School vs New School, traditional vs technology, wrong vs right…but this isn’t the case at all. More often than not, both sides are saying the same thing - they’re just using two different languages.


The reality is many of baseballs’ traditional terms have recently discovered new measurables to quantify them. Organizations who can unite these languages across all levels will have a distinct advantage. Understanding traditional terms and how the new measurements apply can assist in getting scouts, player development staff, and the front office all on the same page when making decisions. This post will dive into a handful of traditional pitching terms one might hear behind the backstop among Scouts. We will then connect some of the terms with measurables and look into how these measurables might help to grade pitcher value.

For generations, baseball has been littered with distinct verbiage. The baseball scouting world possesses its own lexicon of terms, accumulated over decades, to aid in the description of players. This language is both colorful and illustrative, but takes time to learn and understand. A novice to the baseball world typically has a difficult time understanding these terms when hearing them for the first time. One such example used to describe a pitcher’s arsenal is as follows, “Kids got a heavy fastball, absolute bowling ball, and he throws it downhill for strikes; he combos that with a tight, frisbee slider, he’s someone you can dream on.” (Was that English?)

Let’s look at this description closer.


Heavy Fastball / Bowling Ball – a fastball with sink. A pitch that is tough for the batter to square up and has been traditionally thought to yield a higher amount of ground balls.


Throwing Downhill – throwing a pitch at a downward angle to the plate, as opposed to the pitch having a flat trajectory. Fastballs with downward angle have the ability to miss more barrels and produce a higher percentage of ground balls and lower percentage of hard contact from opposing batters.


Tight Slider – a slider with later and sharper break than the average slider. Sliders with later break are more difficult for the batter to pick-up because they travel along the same trajectory as the pitcher’s fastball for a longer period of time before they break. They also tend to break after the hitter has decided to swing, typically generating a higher swing and miss rate from the batter.


Frisbee Slider – a slider with significantly more horizontal movement and not as much vertical drop. The frisbee slider is a larger, loopier slider than average. It typically sweeps across the plate, and is more effective against same side hitters (RHP vs RHH, LHP vs LHH) than opposite side hitters (RHP vs LHH, LHP vs RHH).


Other phrases include dead fish (above average change-up), hammer (above average curveball), exploding fastball (fastball that appears firmer than it is), big daddy breaking ball (curveball with above average movement). These phrases are merely a glimpse into baseballs’ traditional verbiage.


In recent years a technological evolution has taken baseball by storm. Often referred to as a “New School” approach to baseball, it is equipped with measurables, data sets, multi-linear regressions, standard deviations, and a whole bunch of other terms that appeared in my collegiate statistics class. The ability to quantify outcomes (pitches, swings, etc.) has allowed baseball to prove some things correlative value within certain standard deviations. It’s a new way of examining baseball, chaperoned by its own, often intimidating, language. Since this new language has become more and more popular, it's often assumed to have taken the place of the “Old School” language. However, the reality is these languages compliment each other.


With the help of pitch tracking systems, such as Rapsodo and Trackman, we are able to quantify several facets within a given pitch. Utilizing today's technology we are able to define key pitch characteristics down to a fraction of an inch. We can now compare every pitch thrown by pitchers to help quantify which pitches have what degrees of each characteristic. These measurables allow a more accurate comparison to exist, in the quest to discover the most effective pitches in getting batters out.


Let's take a closer look at the previous description of a pitcher’s arsenal and attempt to assign an appropriate measurable to each characteristic.


Heavy Fastball / Bowling Ball – a fastball with a lower spin rate than the average fastball.


Throwing Downhill – a fastball with lower Vertical Approach Angle than the average fastball.


(Vertical Approach Angle tells us how “steep” or “flat” the pitch was when it crossed home plate. Flat pitches approach at an angle more parallel with ground. While steeper pitches have a more perpendicular angle to earth, oftentimes making it more difficult for the hitter’s swing path to get on plane with the pitch.)


Tight Slider – a slider with higher spin rate than the average slider. This also is affected by the sliders “spin-efficiency” or “gyro-spin”.


Frisbee Slider – a slider with a higher than average amount of Horizontal Movement and average to below average amount of Vertical Movement. (You can check out this Simple Sabermetrics video regarding slider movement profiles for more information regarding the different shapes of sliders.)


It might take a little work in the beginning, but these traditional terms and new school measurements match up in a complimentary fashion. The ability to define each of the traditional terms and match them with a measurable data point provides great value to an organization. This ability allows the organization to quantify the degree of which each individual possesses a certain skill set; and then assign them an accurate evaluative grade.



Let's take a look at two similar MLB pitchers who throw “heavy” fastballs. Both are tall, RHP, lower arm-slots (traditionally referred to as ¾), who challenge hitters with bowling ball sinkers. Let’s attempt to quantify the difference between their “heavy” fastballs.



Erick Fedde, RHP of the Washington Nationals, is listed at 6’ 4” and delivers the ball from a ¾ arm-slot. In 2020, his average sinker velocity has been 93.5 mph, which he’s utilized to generate a high percentage of ground balls.



Zachary Eflin, RHP of the Philadelphia Phillies, is listed at 6’ 6”, and delivers his sinker from a ¾ arm-slot. In 2020, his average sinker velocity has been 93.7mph, which he’s utilized to generate a high percentage of ground balls.


Fedde and Eflin are two similar pitchers at first glance. Using the new measurables, we can decipher differences between their “heavy” fastballs.


The MLB average spin rate on a fastball is between 2200 RPM - 2250 RPM. In 2020, Fedde’s fastball averaged around 1850 RPM, Eflin’s fastball sat around 2050 RPM. Expectedly, both are well below the MLB average, with Fedde’s being 200 RPM lower than Eflin’s.


The MLB average gound-ball percentage (GB%) on fastballs is 44%. Fedde’s fastball has produced ground-balls at a 55% clip, while Efflin’s has yielded around 50%. Expectedly, both are well above the MLB average, with Fedde’s being 5% higher than Efflin’s.


Based on the numbers, one can conclude Fedde throws a “heavier” fastball than Efllin.



When comparing two pitchers of similar skill set, the new measurables allow us to quantify what degree of a particular characteristic each pitcher possesses. The new measurables add numbers to the traditional terms. Although these two languages have been pinned against each other, more often than not they are describing the same thing. The ability to quantify the things baseball has been saying for years allows us to enhance the use of traditional terms. Being able to utilize the numbers brought into the game by the new technology allows for more effective evaluation of each player's skill set.


More Reading:

https://www.draysbay.com/rays-prospects/2015/12/17/10301428/rays-prospect-brad-schreiber-has-a-heavy-fastball


https://www.letstalkpitching.com/t/throwing-downhill-vs-percieved-velocity/5029


https://www.drivelinebaseball.com/2016/11/spin-rate-what-we-know-now/


https://wfusportsanalytics.files.wordpress.com/2019/12/launch_vertapprangle.pdf


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