What Makes a Good Fastball?

Velocity is king, or is it?

May 06, 2025

Intrudction

This article will cover the characteristics of fastballs and explain what distinguishes the best and worst fastballs in MLB from others. I will look at groups of fastballs categorized by their “scouting grade” and highlight the characteristics that lead to that grade. I will be using my tjStuff+ model to assist with the categorization of pitches and slot each pitch into the 20-80 Scale. I will be specifically covering 4-Seam Fastballs.

20-80 Grade Scale

Before we get started, let’s take a look at the 20-80 Grade Scale that it used when assessing baseball players. The scale is based off a normal distribution where the mean is 50 and standard deviation is 10. For those unfamiliar with the Normal Distribution, think of it like a “bell” where most of the population is clustered around the center and then it flares outwards and peters out near the ends. Due to its shape, it is commonly referred to as the “Bell Curve”.

The clustering around the mean indicates that majority of the population is around average. In baseball we consider players that live in the region bounded by ±1.0 Standard Deviations to be 40-60 Grade players. This area encapsulates ~70% of all players. As we approach either end of the curve, the proportion of the population dwindles as these groups of players deviate from the average, both positively and negatively.

Here is a table which summarizes the 20-80 scale and assigns the grade to its respective standard deviation (σ) value. I will refer to this table throughout this article as I assign each fastball its respective grade.

Fastballs

There are a lot of aspects that make up a fastball. Most importantly is its velocity. As we work through each grade, we will see that as velocity increases, the lower bound of its grade range increases. Another factor that is important to fastballs is its movement. 4-Seam fastballs are typically characterized by their high backspin which induces positive vertical break. This means that fastballs “defy” gravity as they drop less than if no spin was imparted on the ball. Generally, higher induced vertical break (iVB) is desirable, but the consideration of factors like release height and arm angle add more nuance to the discussion. I will provide examples of the interactions between these variables and what makes them favourable or not. Horizontal break is also important as it can disrupt a batter’s expectations. The final factor that I consider essential is extension. Extension is simply the distance down the mound that a pitcher releases the pitch. Higer extension is desirable because it increases the perceived velocity of the fastball due to the shorter distance the ball requires to get to the plate.

Each group will have multiple examples of a pitch of that specific grade and each pitch will have a video example as well as a detailed breakdown.

20 Grade

These pitches are the bottom of the barrel fastballs. We only see a handful of these pitches in MLB because they generally return poor results. These pitches typically have no redeeming qualities, ranking well below average in multiple aspects, with velocity typically being the worst.

Kyle Hendricks

Key Characteristics: League worst velocity, poor shape, steep VAA

Hendricks throws the slowest fastball in the Majors at just 86.5 MPH, nearly 8 MPH slower than league average. That alone makes it one of the least effective fastballs in MLB, but it gets worse. The pitch exhibits below average ride from an above average vertical release point. This combination isn’t ideal because it leads to a steeper fastball, which batters historically perform well against. And would you look at that; Hendricks’ fastball is one of the steepest in MLB, having a -5.7° Vertical Approach Angle (VAA). To top it all off, Hendricks sits in the bottom of MLB in terms extension.

The pitch grades out in the 0th Percentile according to tjStuff+ with a value of 83.

Bryce Elder

Key Characteristics: Poor velocity, “Deadzone” Shape, poor extension

Elder doesn’t have league worst velocity, extension, or VAA, however he joins Hendricks in the “20 Grade” group because his fastball has decidedly “deadzone” shape. A “deadzone” fastball is a fastball that has a movement profile which is characterized by well below average iVB for its slot. In Edler’s case, he releases his fastball from a 6.5’ release point with a high 3/4 arm angle. We usually see pitchers with this kind of release have above average iVB as they should have an easier time imparting backspin because they are more on top of the ball. To put it bluntly, Elder’s fastball has horrendous shape while also sitting near the bottom of league in essentially all other aspects.

The pitch grades out in the 0th Percentile according to tjStuff+ with a value of 83.

30 Grade

These pitches are slightly better than the predecessors. These pitches usually exhibit at least one average feature to keep it from the bottom. However, these fastballs are still considered very weak and are characterized by their poor velocity and/or shape.

Carlos Carrasco

Key Characteristics: Poor velocity, “Deadzone” Shape, above average extension

Carrasco’s has the same issue as Bryce Elder: its deadzone shape and poor velocity. On the surface, the pitches each have very similar traits; however, Carrasco’s above average extension pushes it out of the basement. With that being said, it is still one of the weakest fastballs in MLB, and has performed as such this season.

The pitch grades out in the 3rd Percentile according to tjStuff+ with a value of 86.

Matthew Liberatore

Key Characteristics: Average velocity, “Deadzone” Shape, average extension

Liberatore finally gets us to league average velocity as his fastball sits at 94.3 MPH. Despite the solid velocity, he sits in the “30 Grade” tier because there really isn’t anything redeeming about his fastball. It has average velocity and extension while also exhibiting “deadzone’ characteristics that plagued both Bryce Elder and Carlos Carrasco. Liberatore gets a little bit of a bump thanks to being a southpaw, but it isn’t enough to keep him from the bottom of the league.

The pitch grades out in the 2nd Percentile according to tjStuff+ with a value of 86.

40 Grade

These pitches separate themselves from the lower grades thanks to at least one key feature. They are still considered below average pitches overall, but are less detrimental.

Tyler Anderson

Key Characteristics: Very poor velocity, elite iVB, below average extension

Tyler Anderson is a fantastic example of how a pitcher can make up for below average velocity. Anderson, like his teammate Hendricks, throws a sub-90 MPH fastball, but he leverages his ability to generate ride on the pitch to push it closer to average. Anderson throws from a higher slot and generates nearly 20” iVB on his fastball, making it elite in that category. Again, its lack of velocity is dragging the grade down, but its movement mostly makes up for that deficiency.

The pitch grades out in the 19th Percentile according to tjStuff+ with a value of 96.

Luis Castillo

Key Characteristics: Average velocity, league worst extension, elite VAA,

I have a love-hate relationship with Luis Castillo. He has been a great pitcher throughout his career, but we are seeing some decline in his profile, most notable his fastball. This season, it sits around league average velocity and movement from his side arm delivery with league worst extension. Pitches that exhibit average characteristics across the board typically grade out as below average because there isn’t much standout about the offering. Castillo has remained effective thanks to his ability to locate his fastball high in the zone consistently.

The pitch grades out in the 17th Percentile according to tjStuff+ with a value of 95.

Roki Sasaki

Key Characteristics: Plus velocity, plus extension, poor iVB, poor VAA

Roki Sasaki was the prized prospect in the international free agent signing period, yet he hasn’t looked all too great thus far. A lot of his struggles stem from his fastball. It averages 96 MPH with 7.1’ extension, well above league average for a starter, but its shape has made it one of the least effective offerings in MLB. From his 6.1’ release height, he generates poor iVB which gives the pitch a very steep VAA. The negatives of the pitch outweigh its positives, and demonstrates that velocity isn’t everything.

The pitch grades out in the 20th Percentile according to tjStuff+ with a value of 96.

50 Grade

These pitches are squarely average. There are many ways to get to an “average” fastball, but they usually have multiple aspects that are above average with at least feature holding it back.

Matt Strahm

Key Characteristics: Below average velocity, elite arm-side run, plus iVB

Strahm is our “below average” velocity example for this group as he doesn’t let his fastball’s poor speed hurt its grade. Strahm exhibits elite run and plus ride on his fastball from the left side which gives it unexpected movement. the fastball’s lack of velocity drags the grade down, but its beneficial shape props is back up.

The pitch grades out in the 58th Percentile according to tjStuff+ with a value of 103.

Yoshinobu Yamamoto

Key Characteristics: Plus velocity, average everything else

Yamamoto has been excellent this season, and the improvements to his fastball are a big reason why. Its characteristics are essentially average across the board with his velocity sitting above average. There isn’t anything negative about the pitch, but there really isn’t much about the shape that makes it standout, hence the average grade.

The pitch grades out in the 54th Percentile according to tjStuff+ with a value of 102.

Paul Skenes

Key Characteristics: Elite Velocity, average extension, below average iVB

Skenes has an average fastball? No way! Well, from an objective standpoint, Skenes doesn’t particular have a great fastball. Its elite velocity was the talk of the town throughout his college career and it translated well into MLB, but the concerns about its shape still hold it back. Skenes doesn’t have “deadzone” shape on his fastball due to its elite arm-side run, but its poor iVB is its biggest issue. It will likely perform well throughout his career thank to its velocity, but his fastball is not without its flaws.

The pitch grades out in the 55th Percentile according to tjStuff+ with a value of 103.

60 Grade

These pitches are above average, or colloquially known in the baseball word as “plus”. These pitches typically have multiple above average characteristics, but are held back at least 1 feature or the lack of an elite feature.

Kris Bubic

Key Characteristics: Below average velocity, plus extension, plus iVB for slot

Bubic isn’t going to blow batters away with velocity; he actually sits well below league average with a 92.2 MPH fastball. What makes Bubic’s fastball a “plus” pitch is how he leverages his delivery and ability to generate ride from the left side. Bubic generates near elite iVB from a below average slot with plus extension to create a deceptively flat approach. It has been the key to his smooth transition back into the rotation and continues to exhibit how an elite shape can make up for a lack of velocity.

The pitch grades out in the 66th Percentile according to tjStuff+ with a value of 105.

MacKenzie Gore

Key Characteristics: Plus velocity, plus extension, plus iVB

Gore’s fastball is a great example of a fastball that has plus characteristics across the board, but no standout aspect that pushes it up into the next tier. Above average velocity, extension, and ride makes it a good, but not a great pitch.

The pitch grades out in the 75th Percentile according to tjStuff+ with a value of 107.

Hunter Brown

Key Characteristics: Elite velocity, plus extension, average iVB

Brown’s fastball is our “elite velocity” example for this group. Brown supplements the velocity with plus extension, but it falls short in the iVB department. It has expected movement given his slot which holds it back from reaching the next tier.

The pitch grades out in the 77th Percentile according to tjStuff+ with a value of 107.

70 Grade

These pitches are elite, or colloquially known in the baseball word as “plus-plus”. These pitches typically have at least one elite characteristic which pushes them into this tier, but are held back by some other aspect.

Alex Vesia

Key Characteristics: Below average velocity, league best iVB

Vesia may have the most outlier fastball in baseball. Despite sitting in the low 90s, Vesia’s fastball grades out as plus-plus thanks to its league best ~22” iVB. The ride on the offering is aided by his over-the-top release, but it is still miles ahead of the pack.

The pitch grades out in the 91st Percentile according to tjStuff+ with a value of 112.

Jeremiah Estrada

Key Characteristics: Elite velocity, plus extension, elite iVB

Given its elite velocity and extremely flat VAA, Estrada’s fastball has all the ingredients of nasty pitch. It might be crazy to say, but the reason why this pitch isn’t “80 Grade” is due to its lack of velocity. Yes, a 98 MPH fastball is somehow being held back because it isn’t fast enough. The gap between 70 and 80 Grade is razor thin, so every tick matters. All in all, Estrada’s fastball is one of the best in baseball.

The pitch grades out in the 97th Percentile according to tjStuff+ with a value of 116.

80 Grade

These pitches are the best of the best. Their shape may not be better than others in lower tiers, but they contain essentially no flaw and are buoyed by their league best velocity.

Mason Montgomery

Key Characteristics: League best velocity, plus extension, elite iVB

Montgomery consistently hits triple digits from the left side and generates elite iVB with above extension. It is in contention for the best fastball in MLB, and tjStuff+ would agree. It mimics Estrada’s fastball, but that extra tick of velocity is what propels it into this tier.

The pitch grades out in the 100th Percentile according to tjStuff+ with a value of 120.

Mason Miller

Key Characteristics: League best velocity, plus extension, plus iVB

Miller’s fastball averages 100.8 MPH. That is basically all I need to say here. He pairs its league best velocity with plus extension and above average ride to make one of the deadliest pitches in MLB.

The pitch grades out in the 99th Percentile according to tjStuff+ with a value of 119.

Conclusion

Whether it be a low velocity rising heater or a blazing fast fireball, fastball effectiveness comes in many shapes and sizes. I hope this deep dive helped you understand and appreciate fastballs and the characteristics that separate the best from the rest.

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