The Best Fastballs in the Minors

Fastballs are the foundation of most pitchers' arsenal. Even as the usage of them falls every year, the fastball is still by far the most used pitch league wide. If a pitcher has an elite fastball, it is very likely they will find success in the major leagues. So who are some pitchers with elite fastballs in the minors? That is what we are looking at today. 


So what makes a good fastball? Is it results? Is it vertical movement? A low release height? Raw velocity? Command? The answer is of course all of the above. For a pitch to truly be elite it has to be able to do multiple things. If a pitch is not performing, it probably is not an elite pitch as things currently stand. If the pitch is performing, then that doesn’t necessarily mean it is elite. In this article, I will highlight five fastballs with both elite shape, and elite production, and outline why they work as well as they do. 


Andrew Moore

Key Stats: 40.4% CSW, 55% ZSwing, 27.4% Chase, 45.8% Whiff, .411 xwOBAcon


Andrew Moore was sent to Cincinnati as the throw-in to the Luis Castillo trade. He deserves a lot more attention than what he received in the deal because Moore is one of the best relief prospects in baseball. It all starts with an 80-grade fastball. 


Andrew Moore sits at 96.6 MPH and can reach back for triple digits in a pinch. His fastball actually plays above that velocity due to plus extension on the pitch. The pitch has slightly above-average ride with 16.7” IVB, but the real appeal is in the 5.4’ release height. Andrew Moore with his combination of vertical movement, and release height has a -3.32° VAA in the top third of the strike zone. That is the same top-third VAA as Josh Hader who throws at very comparable speeds. 


Andrew Moore also has 13.7” of horizontal movement, which is elite for a four-seam. The pitch is coming out of a very low arm slot which creates interesting angles horizontally with the fastball. I think he could easily make those angles even better by adjusting his mound positioning. At the present time, Moore is hugging the first base side of the rubber when he pitches. This leads to his HAA being depressed, and there is very little benefit to hugging that side of the rubber. It makes a lot more sense for Andrew Heaney to hug the third base side (or even actually stand in the middle for command purposes) as it’ll give the fastball a zigzagging effect and make it an elite called strike weapon when located to the gloveside. 


Andrew Moore has elite vertical angle, and fantastic horizontal angle on his fastball along with premium velocity. Those three features in tandem lead to truly special results. The pitch has a 45.8% whiff rate which is tied for the highest whiff rate of any fastball thrown 400+ times at any level this season. He also has the 15th lowest in-zone-swing rate against the fastball. This is out of 2048 qualifiers. His fastball command is somewhat iffy, but his stuff will still play as one of the best pitches in baseball. 

The secondary stuff has promise as well, but has its own demons to overcome. The slider is a gyro that sits just above 85 MPH and misses bats. The extreme tail, and poor secondary command limit his ability to get hitters to chase, however. The curveball is a spin mirror to the fastball with a comparable axis, spin rates, and efficiency. As a result, he gets chased 35% of the time with extreme movement because of the mirroring effect. The curve is an above-average pitch but command holds it back. Andrew Moore also has dabbled with a changeup that has promising shape in the past. 


The fastball will get Andrew Moore to the majors, and insure him a role in a major league bullpen, but he needs to develop feel for at least one of his secondaries to reach his potential as one of the best relievers in the sport. My preference is that he focuses on the curveball, but all three could theoretically work. 


Tyler Thornton

Key Stats: 34.8% CSW, 79.4% ZSwing, 28.7% Chase, 47.1% Whiff, .344 xwOBAcon


Tyler Thornton was the Guardians 17th-round draft pick out of Arizona State back in 2021. He didn’t pitch at all in 2021 after the draft, and was moved to the bullpen when he made his debut this past season. He was electric in that role as he posted a 40.6% strikeout rate but battled command issues that deflated the actual results. There is only one real reason why Thornton missed so many bats and that reason is the flattest fastball in baseball. 


The fastball is a unique pitch because of two traits. The first is the release height which is a total outlier at 4.7’ on average because he is literally throwing from one knee. That release height is obviously low, but what makes it special is his ability to spin the ball. Thornton averages 2484 RPMS on his fastball and throws with a 1:19 spin tilt. He has high spin efficiency, and as a result gets a ton of movement on both planes. 

The fastball has 16.3” IVB, just 0.2” above league average. That might not sound like anything special, but given the context of his release, it is. Only one other player has a release height under 5’ with at least league-average vertical movement. That only player is the Red Sox Daniel Nuñez in the DSL academy who only throws 88.3 MPH and has a release height of 4.97’. The combination of vertical movement from such a low release makes Thornton a total outlier. As a result, he has the second flattest four-seam VAA in the top-third of the strike zone of any player at any level (Min 300 fastballs) at -2.84°. 


The only player with a flatter four-seam is Adam Cimber. Cimber throws 86.4 MPH. Thornton, however, actually has pretty damn good velocity.  He sits at 93.6 MPH, and can reach back for more in a pinch. The combination of velocity, and the flattest competitive fastball in the sport is extremely overpowering and leads to a 47.1% whiff rate. I think you can get him throwing even harder too, with some strength progression as he still has room to add muscle to his 6’3” frame. 


The one problem with the fastball is command. Thornton struggles to hit his spots with any consistency and seems to have no control over the horizontal location of the pitch. He misses to both sides almost equally as often, so there’s some not some easy trick to fix him. The fastball does still wind up in the zone nearly 50% of the time, but there are too many pitches left in very hittable spots, and not enough four-seams above the zone where it plays best. 


The secondaries also leave a lot to be desired. The slider is his first choice, and it’s a sweeper with 12” of sweep that sits just below 80 MPH. It has horrible results with a chase rate below 12%, a Zswing of 70%, and nearly a 30% barrel rate against it. The changeup is hardly thrown and only had a 15% CSW this year. The lack of secondary weapons, and command means that despite true 80-grade fastball on stuff, Thornton is not expected to be an impactful major leaguer. However, the fastball is a great foundation to try to create an impactful player out of. If the Guardians can give him a mid-80s gyro slider, I think it's possible Thornton still finds his way into a high leverage bullpen role. 

Jose Cruz

Key Stats: 34.2% CSW, 63.7% ZSwing, 31.2% Chase, 30.3% Whiff, .272 xwOBAcon


Jose Cruz is different from the other names on this list, because he’s not really a big whiff four-seam fastball type. He utilizes a hybrid sinker with great specs instead. Jose Cruz was signed by the San Francisco Giants as an international free agent from the Dominican Republic back in 2017. He struggled at first, but five years later, the still only 22-year-old Cruz posted a 2.06 ERA in 52 innings at Low-A, and made it clear to everyone that he has a future in the major leagues. The fastball is half of the reason for Cruz’s emergence. 


Jose Cruz sits at 95.3 MPH on the heater, and can reach back for 99 in a pinch. The pitch is a tailing pitch with 18.9” of run to the armside. That is more than all but nine fastballs (Four-seam or sinker) thrown at least 400 times at any level this season. The elite run to the armside, combined with a 2.8’ horizontal release, leads to some crazy results with the pitch. He can get both chases when working on the armside, or called strikes when pitching to the gloveside. 


The fastball also misses bats because he throws from a 5’ release height. The fastball is more of a two-seam than sinker as he has high spin efficiency and high spin rates, so the two-seam still has 12.3” IVB. That is enough that when paired with the low release, Cruz has a -3.44° VAA in the bottom third of the strike zone which is in the 97th percentile of all fastballs at any level. As a result, Jose Cruz has a 52.6% whiff rate on fastballs in the upper third. 


The sinker when working down is one of the best sinkers in the game. On pitches in the bottom third, it’s a 40% in-zone swing rate. He also gets groundballs 73.3% of the time down in the zone. When he goes up, it’s one of the best whiff offerings in the sport and gets chases just over 36% of the time. He throws hard with tough angles that lets the fastball play up in any location. If he starts manipulating his pitch location to suit the count and game leverage, he can be nearly unbeatable with the fastball. 

Jose Cruz is also unique as he is the only player on this list that you can argue the fastball isn’t his best pitch. At least in terms of results, the changeup has it beat by a considerable margin. He has the most horizontal movement of any changeup thrown 250+ times this season at any level. He cuts the sinker vertical movement in half, and it gets both more chases and whiffs. When he misses gloveside it gets called strikes. It also was only barreled once this year. 


The slider is completely useless and why Jose Cruz was moved to the bullpen. He has a bad shape with no tunnels or feel. The pitch has .452 xISO against it and a barrel rate over 30%. If you eliminate the slider, opponents hit just .136/.244/.205 against him. Cruz is rule 5 eligible this year, and if left unprotected, I would eagerly take him and have him use the FB/CH only in relief where he should be incredibly dominant in the long term. Command woes will hurt early performance, but the long term upside is one of the best relievers in the sport. 


Zach Brzykcy

Key Stats: 34.5% CSW, 77.5% ZSwing, 33.2% Chase, 39.6% Whiff, .358 xwOBAcon


That NL East Reliever I teased in the Evan Gates article who ranked #1 on the Data Driven Top 1000 Pitching Prospects? That is Zach Brzykcy. Zach Brzykcy went undrafted during the 2020 draft when it was truncated to five rounds. The Virginia Tech product latched on with the Nationals, and has more than proven himself worth the zero-risk investment. He climbed all the way from A+ to AAA this year, and posted a 1.76 ERA in 61.1 innings with a 38.5 K%. 


Brzykcy has the most boring fastball on this list, but it also is possibly the best. It’s your stereotypical elite fastball, but just slightly better. The fastball is thrown at 95 MPH and touches 98. He has a generic release point with a release height of 5’11” and a horizontal release of 0’11”. If you haven’t realized it yet, the appeal of the fastball is vertical movement. Brzykcy averages 22.3” IVB on his four-seam fastball. The only fastball thrown 400+ times with more movement is his teammate Matt Cronin. The reason he’s not on this list, is that he throws 4 MPH slower. 


The fastball movement is special and leads to a lot of swings and misses against the fastball. However, the real separator for Brzykcy is that he has above-average fastball command. 72.4% of his four-seam fastballs wind up in the top-half of the strike zone. Just 3.9% of his pitches are waste pitches. Brzykcy is consistently locating the fastball where it can play the best, and letting his movement play to the fullest it is capable of. 

Brzykcy has interesting secondary stuff as well. The changeup has good fade with 7.5 MPH of velocity separation. His command of the pitch is only average, but it still gets both chases and whiffs. The curveball is thrown hard in the low-mid 80s, but has below-average movement. It’s a solid called strike weapon, and he throws it in the zone over half the time, but uses it far too often in obvious swing counts, and that tends to lead to some walks.  


The combination of command and stuff makes it very likely that Zach Brzykcy one day will claim a high leverage role in the majors. That day might be his first day in the majors on opening day next year, as Brzykcy is arguably already the Nationals’ best reliever. This is the safest MLB contributor on the list, but he probably has the lowest upside- and that upside is still an above-average closer.


Nick Frasso

Key Stats: 34.4% CSW, 62.5% ZSwing, 36.3% Chase, 30.5% Whiff, .298 xwOBAcon


Nick Frasso was sent to the Los Angeles Dodgers in a deal for Mitch White, and the fastball is a large part of why the Dodgers targeted him in particular. The pitch is a hybrid that dominates batters of both handedness through every method imaginable, and I expect that to continue in the major leagues.


Nick Frasso has a unicorn fastball. He throws it at 96 MPH with above-average extension and total outlier movement and angle. He has touched triple digits. The pitch averaged 16.3” IVB and 12.8” HB this year on 581 pitches. That is an outlier movement on its own- there are zero major league fastballs (FF+SI averaged) that average as much IVB and as much HB. The movement is hardly what matters here though. 


Nick Frasso throws from a 40.3” RelX and a 72.4” RelZ. This is a totally unique arm angle. There is only one pitcher in all the majors with as high of a release height and wide of a release side: Dylan Floro. Floro has gotten great results out of the pen spamming a fastball with bad shape 65% of the time. The reason is the angle that creates an extreme dichotomy in swing rates based on what side of the plate he throws it to. He can use it for called strikes to his gloveside or chases to his armside. 


Nick Frasso takes what Floro’s fastball is and turns it up to an 11. He throws his fastball 3.5 MPH harder and has two inches more movement on both planes. As a result, the fastball is practically unprecedented. It’s a unique release and unique movement with top-end velocities. The results this year were also unprecedented. The fastball saw just a 48.5% Zswing when thrown to the gloveside with a mere 12.4% chase rate. When working to the armside it’s a 75% Zswing and a 51% chase rate. 

The value of a fastball that changes shape based on what side it is thrown to is immense. Early in counts, called strikes reign supreme. Frasso can take advantage of that early with gloveside fastballs that he lands in the zone 64.7% of the time. There is also little risk in hard contact off the fastball early if they do swing- especially against right-handed hitters. The fastball has extreme horizontal movement that evades barrels and the tough angles that make it even harder to square up. As a result, he has just a .270 xwOBAcon on the gloveside fastball.


When he is ahead in the count and looking for a whiff, the armside fastball is his best friend. Frasso can get chases at an elite clip and gets whiffs at a high rate when working to the armside. The versatility of the fastball lets it essentially function as two different pitches, and due to the bias of the location, he plays above the natural stuff as long as he has decent execution. Given the quality of the fastball, it’s two separate elite pitches. 


The fastball is the main attraction in Frasso’s arsenal, but it is far from the only one. He has a slurve in the mid 80s that is practically guaranteed to perform with half-decent command given his wide release. The changeup shape is even better. He has over 18” of fade and good depth with 11 MPH of velocity separation. The changeup misses 46% of bats in the zone. The problem with both secondaries, and what holds Frasso back from being one of the best pitching prospects in the game is command. Frasso zones both his secondaries less than 30% of the time, and frequently will throw uncompetitive pitches. If he can figure out his secondary command, it’s a front-of-the-rotation profile given how good the fastball is. 

Stay Tuned for part two of this six part series. Next time, I will cover the best fastball hitters in the minor leagues.