What is Stuff+? Quantifying Pitches with Pitch Models

By Chris Langin, Pitching Coach

The artwork of “pitching” has many variables related to it, some simply quantifiable… others not a lot. Each pitcher, coach, and group is consistently in a battle of weighting these variables in a fashion that maximizes growth and efficiency on the sector.

Whereas there’s little settlement on how necessary “secondary” variables similar to deception and sequencing are in direction of producing outs, it’s usually accepted that three pitcher skills stand out above the remaining. 

The power to:

  • Command the baseball.
  • Generate ball velocity. 
  • Manipulate the baseball and purchase distinctive motion on pitches.

These three traits include the bonus of being reasonably simple to quantify on the MLB stage. We don’t essentially want a radar gun, nor a pitch mannequin (defined under) to tell us that Aroldis Chapman has a very good fastball.

Nevertheless, given the innate bias related to human evaluators, it’s probably {that a} pitch mannequin can extra reliably detect a 40-grade fastball from a 45-grade one than an evaluator working alone and with out knowledge. Ideally, the mix of sturdy baseball savvy combined with a well-regarded mannequin grants us essentially the most optimum analysis of location agnostic pitch high quality. 

Stuff+ Driveline’s Pitch Mannequin

The Pitch Mannequin we reference at Driveline is called “Stuff+” and is at present going via it’s 4th iteration. As talked about above, the mannequin filters out plate areas (thus traits of command which is measured in a separate metric) and primarily considerations itself with the next ballflight metrics: 

  • Pitch Velocity
  • Vertical Break
  • Horizontal Break 
  • Arm Angle 
  • Launch Extension

The principle influencers are the primary three descriptors talked about: velocity, vertical break, and horizontal break — although, we’ll focus on the necessity to guarantee arm slot context is taken into consideration — together with excessive launch extension values. 

The necessity to account for interactions between these variables is probably not instantly obvious provided that extra motion and velocity usually result in the next high quality pitch. Nevertheless, there are explicit cases the place sure pitches break that useful rule of thumb. 

For instance, extra velocity on breaking balls usually comes with a tradeoff in glove aspect motion. A sinker that good points vertical break often drops in effectiveness, whereas a generic four-seamer that good points vertical break will get an uptick in effectiveness.

When creating choices within the offseason, the power for an athlete and coach to make use of Stuff+ to instantly summarize a 79-mph slider with extra motion in opposition to an 83-mph gyro-esque slider is sort of helpful. Maybe the deviation in stuff+ between the two choices is massive sufficient to decide on one of many choices with minimal bandwidth allocation in direction of bettering or altering on explicit pitch.

Stuff+ is scaled equally to IQ — with a rating of “100” that means that pitch graded out as league common relative to different pitches thrown in that pitch kind bucket. A fastball with a Stuff+ of 75 could be 25% under the league common for fastballs. A curveball with a Stuff+ of 130 could be 30% above the league common amongst all breaking balls. 

The seven “popularized” pitch sorts are rearranged into three distinct pitch buckets — with these pitch sorts competing amongst one another inside their related pitch grouping. 


Breaking Balls


It’s necessary to remember the fact that these pitches compete amongst one another—breaking balls are inclined to decrease run values greater than Fastballs, that means a four-seamer with a Stuff+ of 150 just isn’t essentially equal in “uncooked stuff” to a slider with a Stuff+ of 150. 

Uncooked Pitch Kind Run Worth per 100 pitches Grouped Pitch Kind
SL -0.98 Breaking
CT -0.59 Breaking
CB -0.58 Breaking
CH/SP -0.42 Off Velocity
FF -0.19 Fastball
SI -0.14 Fastball

With out additional ado, let’s see some examples of Stuff+ in motion. 

4-Seam Fastballs

2021 4-Seam Averages

Handedness Velocity Horizontal Vertical Launch Peak Extension
RHP 94.1 7.5” 16.4” 5.9’ 6.4’
LHP 92.8 7.8” 16.6” 6’ 6.3’

Highest graded four-seamer in 2021 (that was a strike) 

Velo: 102.4 (99th percentile), VB: 18.7″ (eightieth), HB: (-) 2.2″ (tenth), Stuff+: 350

Chapman is nicely regarded for having maybe essentially the most electrical arm the world has ever seen.  Of the highest 10 graded fastballs this season, he owned 8 of them. His 101.5+ mph throws are outrageous outliers, as they’re thrown 4 miles per hour tougher than ninety fifth percentile four-seam velocity (97.6). 

Daniel Bard vs. Mike Fiers

Daniel Bard Metrics, Velo: 98.6 (98th percentile), Vertical Break: 13.5″ (fifteenth), Horizontal Break: 10″ (67th), Stuff+: 90

Mike Fiers Metrics, Velo: 89.8 (ninth percentile), Vertical Break: 20.4″ (92nd), Horizontal Break: 11.5″ (eightieth), Stuff+: 80

Within the instance above, these hurlers deviate considerably in how they get hold of their close to league common four-seam fastballs. Bard is among the many league leaders in spin and fastball velocity, however suffers from important inadvertent minimize at launch.

The result’s a pitch that’s left with reasonably unremarkable motion traits relative to competing fastballs throughout the league. Fiers has thrown 51% heaters throughout his 10-year main league profession regardless of averaging 89.4 miles per hour. He obtains important whole motion on his heater, giving him a heater that ranks round league common when he cranks it up into the low 90s. 

4-Seam high quality is predominantly a results of two issues: velocity and vertical break. For those who mix Bard’s velocity with Mike Fiers motion profile, you kind of get Michael Kopech, who ranked 2nd within the league in Stuff+ on his four-seamer at 225. 

Arm aspect run, and even minimize, does play a task within the potential of the providing — with pitchers which can be at both excessive usually grading out extra favorably. Gerrit Cole is an instance (1st in Stuff+) of a pitcher who obtains important arm aspect run and carry — whereas Clayton Kershaw has been a beneficiary of excessive carry mixed with chopping motion on his heater for years.


2021 Sinker Averages

Handedness Velocity Horizontal Vertical Launch Peak Extension
RHP 93.4 15.5” 9.3” 5.7’ 6.3’
LHP 92.1 15.6” 9.4” 5.8’ 6.3’

Highest graded Sinker  in 2021 (that was a strike) 

Bummer is in a category of his personal in terms of left-handed Sinkers. His 191 Stuff+ common not solely leads the league for sinkers, however it’s 57 factors higher than the following finest left-handed sinker (Gregory Soto). Bummer accomplishes this with ninetieth percentile velocity from the left aspect and the power to control the pitch (largely via seam shifted wake) in order that it strikes in only a lateral course — leading to a pitch that averages lower than an inch of carry. 

Aaron Bummer movement by pitch type

Sinkers differentiate from four-seamers in some ways. The obvious is that the sinker’s worth is tied in direction of producing low run worth contact within the type of floor balls. A mean four-seamer will probably outweigh a “good” sinker in its potential to generate whiffs, nevertheless it gained’t essentially outweigh it in its potential to negate runs. The mannequin at present is agnostic in direction of how the motion is created (spin-induced vs. non-magnus) ; it solely cares that the motion and velocity is generated in some method. 

Our Stuff+ mannequin permits us to place four-seamers and sinkers on the identical scale, permitting us to rank them impartial of their differing run prevention traits. 

Joe Kelly vs. Dillon Tate

Joe Kelly’s sinker is much like the Bard instance above in that its above common score (113) is nearly fully accounted for by its velocity (97.7). Kelly does at the very least obtain above common arm aspect run, however his common sinker doesn’t determine as having a singular motion profile resulting from its lack of depth. Because the pitch has an extra inch of carry relative to the league common sinker.  

Dillon Tate, who didn’t even start throwing the pitch till 2019, is ready to generate a major quantity of depth on the pitch (88th percentile), together with above common arm aspect run (77th). While you add in his velocity (95.5) it’s a bit simpler to grasp why the providing charges 32 items forward of Kelly’s (145). 

Arm Slot Context

Fastballs additionally require us to take a look at arm slot context previous to offering a last judgement – our mannequin is conscious of the impact slot deviation has on stuff as nicely. 

Blake Snell vs. Josh Hader

Whereas Snell beats Hader handedly in all the important thing metrics we’ve mentioned for the four-seamer — Hader’s potential to impart nicely above common carry and velocity on his four-seamer with one of many lowest arm slots within the league proves superior. 

Four-seam release height expectation

If we bin pitchers by 0.2 toes increments, we will see that pitcher’s with Snell’s slot (6.5’+) usually come outfitted with extra keep it up their pitches. Whereas it’s tough to clarify exactly why pitchers who defy their launch expectation obtain a profit, we all know they do.

Pitchers who’ve decrease slots are capable of throw pitches with flatter vertical strategy angles relative to their excessive slot friends. Nevertheless, Stuff+ isn’t involved with command nor focusing on technique — which has a big impression in how a hurler advantages from that benefit. Thus, deception could be assumed the primary wrongdoer for why pitcher’s similar to Hader defy their uncooked velocity and pitch motion metrics. 


We’ve got moved on from fastballs and are actually onto the breaking ball pitch groupings. Cutters, Sliders, and Curveballs are lumped collectively and evaluated merely off of their ball flight and launch traits. 

2021 Cutter Averages

Handedness Velocity Horizontal Vertical Launch Peak Extension
RHP 89.5 (-) 3” 8” 5.9’ 6.3’
LHP 86.8 (-) 1.8” 8” 5.8’ 6.2’

It is a good reminder that we’re merely discussing the context of a pitcher’s “stuff” versus leveraging a whole arsenal and having a differing intent behind every pitch. This context is of utmost significance previous to diving into cutters – as they’re on the identical scale as curveballs and sliders. 

Highest graded Cutters  in 2021 (that have been strikes) 

Within the instance of Clase and Alvarado, we will see that they every obtain elite scores in several fashions. Primarily, Clase is throwing a extra conventional cutter, with 4 extra inches of sweep  and absurd velocity. Alvarado, who practically matches Clase’s stuff rating on this pitch, is throwing basically a league common slider… at 94 miles per hour from the left-hand aspect! The sting visualization supplies good context, as Alvarado’s drops excess of the league common cutter – basically performing like a gyro ball. 

Nathan Eovaldi vs. Shane Greene

Eovaldi throws a extra conventional again spinning cutter. The pitch ranked about common (104) amongst breaking balls this yr – although it’s function within the arsenal was obvious, because it was combined in at about the identical fee as his CH, SL, and CB – choices usually extra related to lacking bats than producing contact. Greene has extra of a “hybrid” cutter in that it has slider sweep combined with cutter carry… with the speed (87.4) proper in between the typical cutter and slider velocity for a RHP. He additionally leverages a swing and miss breaking ball (SL; 166 Stuff+) 28% of the time. 

Thus, the Cutter is very contextual, with the maximization of stuff not essentially being the very best precedence. That being mentioned, hurlers who’re creating or nice tuning a cutter could also be curious as as to whether or not their pitch performs finest when leaning right into a Shane Greene sweeper kind cutter or sticking with the again spinner that Eovaldi throws. That is the place Stuff+ turns out to be useful, as very slight manipulations can flip a Cutter with a stuff+ of 75 into one that’s 100 with out it simply turning into a slider. 


It’s no secret that the slider has develop into “one of the best pitch in baseball” throughout the league. Run values again up this principle, and utilization of the providing has gone up drastically over the previous 2 many years.  The typical slider had a Stuff+ of 119 in 2021, 25 factors larger than the typical cutter. 

Slider usage trends

2021 MLB Averages

Handedness Velocity Horizontal Vertical Launch Peak Extension
RHP 85 (-) 6.6” 1.4” 5.8’ 6.25’
LHP 84 (-) 6.1” 1” 5.9’ 6.25’

Highest graded Sliders in 2021 (that have been strikes)

Tanner Scott was the Stuff+ king (246) for sliders this season… intently trailed by supination sensation Dillon Maples (233). Scott largely is the beneficiary of unparalleled velocity from the left aspect (88.5) and the power to usually prime spin breakers with out a important lack of velocity – basically turning them into 88+ mph slurves at instances.  

Sliders are usually a bit extra simple – some pitcher’s have to steadiness the form of the pitch amongst the rest of their arsenal, however oftentimes the remaining breaking pitches are match across the slider, which tends to be most pitchers optimum whiff-inducer (particularly to similar handed hitters). 

Zack Wheeler vs. Matt Wisler

Wheeler has extra of an  “overpowering” slider. Within the pitch to Freeman, the motion is starting to imitate that of a cutter… although the elite velocity permits it to take care of its standing as a nicely above common breaking ball (140). Wisler, who is thought for being a one trick pony along with his slider, has extra of a finesse providing. Whereas he trails Wheeler by 13 ticks on this particular pitch, he has greater than 4 instances the sweep and fewer carry.

Sliders have as a lot motion deviation throughout the league as any pitch kind. With whiff-inducing breaking balls being such a precedence as of late, stuff+ ensures that we get our athletes as near their optimum breaker as potential – given present publicly obtainable ball flight and launch metrics. 


Curveballs, essentially the most conventional type of a breaking ball, are our final breaking ball of curiosity. This pitch differs enormously in arsenals – with some performing primarily as get me overs, and others performing because the core putaway pitch. 

2021 MLB Averages

Handedness Velocity Horizontal Vertical Launch Peak Extension
RHP 79.7 (-) 9.9” (-) 11.2” 5.95’ 6.25’
LHP 77.8 (-) 8.7” (-) 9.1” 6’ 6.1’

Highest graded Curveballs  in 2021 (that have been strikes)

We as soon as once more witness the advantages of being left-handed right here. Pomeranz’s curveball is sort of distinctive, because it grades out considerably higher than Shane McClanahan’s CB, who ranks 2nd amongst lefties. Kelly’s curveball is actually wizardry given his unexplainable potential to impart cutter-esque velocity to the pitch whereas nonetheless acquiring elite depth.

Over the course of the season, Kelly averaged league common curveball motion, however threw the pitch 7.5 ticks firmer than the typical righty. Pomeranz is ready to obtain a bit extra of a “downer” profile – that means the pitch has 12-6 motion relative to the league common curveball. 

Adam Wainwright vs. Matt Harvey

Wainwright CB, Velo: 74.8 (thirteenth percentile), VB: (-) 20.1″ (ninetieth), HB: (-) 15.7″ (86th), Stuff+: 110

Harvey CB, Velo: 82.2 (79th), VB: (-) 6″ (twenty fourth), HB: (-) 3.2″ (thirteenth), Stuff+: 95

Since his memorable strikeout of Carlos Beltran within the 2006 NLCS, Adam Wainwright has been recognized for having one of many greatest benders within the recreation. He picked up 225 known as strikes with it in the course of the 2021 season. Whereas the pitch basically omits velocity (6.3 ticks slower on common than a RH CB) it makes up for it with an outlier mixture of depth (17.2”) and sweep (17.4”). Within the instance above, Harvey is throwing extra of a “gyro curve” with the speed (82.2 mph) serving to make up for the loss in motion – permitting it to rank about league common amongst breaking balls. 

Context of the remaining arsenal is a heavy consideration for each curveball. Even so, some undergo from an absence of experimentation, as pitchers with a Stuff+ mannequin in entrance of them could be taught they don’t need to be fairly so strict with the spin course of the providing, or could merely be taught that the pitch performs higher with extra of a gyroscopic form.


Our last pitch grouping is “offspeed” which consists merely of changeups and splitters. We really group these pitches collectively when analyzing them – because the function of a splitter and a changeup is mostly the identical. Moreover, pitcher’s pairing each of them within the arsenal is comparatively uncommon within the states. 

2021 MLB Averages

Handedness Velocity Horizontal Vertical Launch Peak Extension
RHP 85.6 13.9” 5.5” 5.8’ 6.35’
LHP 83.6 14.5” 7.4” 5.85’’ 6.25’

Previous to persevering with, we must always contextualize that offspeed effectiveness is predicated on the differential from the fastball. Which means that as an alternative of taking a look at particular person velocity and break values, we must always have a look at these metrics relative to the fastball. We’ll add an extra desk and take fastball + sinker averages and negate that from a pitcher’s offspeed metrics. 

Fastball Contextual Metrics

Handedness Velocity Horizontal Vertical
RHP/LHP -8 (+)  3.4” (-) 8.1”

On common, pitcher’s drop 8 ticks off their fastball, add practically three and a half inches of arm aspect run, and generate 8 inches of depth relative to their common fastball.

Highest graded Changeups  in 2021 (that have been strikes)

Chapman CH, Velo: 91.4 (7.1 off FF) – forty third percentile, VB: (-) 3.5″ (21.3″ off FF) – 99th, HB: (-) 6.3″ (2.2″ off FF) – thirty third, Stuff+: 294

Williams CH, Velo: 82.6 (13.7 off FF) – 97th percentile, VB: (-) 14.8″ (29.5″ off FF) – 99th, HB: 19.2″ (6″ off FF) – eightieth, Stuff+: 275

Devin Williams “airbender” is among the many video games most well-known pitches. Offspeed “stuff” analysis is arguably essentially the most  tough of the groupings we’ve mentioned – what we do know is that trying so as to add depth on the pitch tends to be a worthwhile funding – as many of the recreation’s finest changeups are approaching or exceed 15+ inches of vertical separation off their fastball. 

Jharel Cotton vs. Alec Mills

Cotton CH, Velo: 78.7 (14.5 off FF, 98th percentile), VB: 6.8″ (14.8″ off FF, 96th), HB: 18.2″ (10.4″ off FF, 94th), Stuff+: 145

Mills CH, Velo: 81.3 (7.1 off FF, forty third percentile), VB: 0.3″ (9″ off FF, 63rd), HB: 10.8″ (-4″ off FF, third), Stuff+: 71

This instance could higher carry to gentle the necessity to contextualize the changeup/splitter off of a pitcher’s fastball metrics. Cotton’s CH is supplied with 7 extra inches of carry relative to Mills, however receives a grade double that of Mills. That is as a result of truth Mills throws a heavy proportion of sinkers, which in a way, chokes out the potential of his changeup. 

pitch movement

With Stuff+, and thus the Blob device inside TRAQ, we will undertaking how a lot including in a excessive quantity of sinkers right into a pitcher’s arsenal would hinder their changeup. For pitcher’s similar to Mills, it’s solely potential additional growth of the changeup isn’t all that potential, as his changeup is dropping a reasonably spectacular 12 inches relative to the typical metrics of his four-seamer. 

Launch Extension

Lastly, we’ll briefly point out launch extension. Whereas it isn’t of extraordinary significance, pitcher’s that deviate enormously from league common’s will definitely obtain a lift (or penalty) due its affect on response time for the hitter. 

When accounting for flight time differential, an extra foot of launch extension is well worth the equal of 1.6 mph.  Although, comparatively few massive leaguers deviate by greater than half a foot relative to the league common – therefore it’s gentle affect  in a majority of hurlers’ arsenals.

Stuff+ Recap

Stuff+ could be counterproductive if abused. It shouldn’t be considered a substitute for any further pitch high quality evaluation. We should keep in mind that Stuff+ is location agnostic and appears at pitches individually. Good baseball instinct remains to be required to contextualize whether or not or not merely maximizing the stuff+ on a given pitcher’s cutter is perfect for his or her particular arsenal.

Stuff+ takes away some bias from the equation and supplies a robust abstract rating for how a pitch charges based mostly on its pitch flight traits and launch parameters. Stuff+’s greatest power is that it captures this with out a want for an enormous pattern dimension – permitting for quick suggestions throughout pitch designs within the offseason.

When utilized correctly, Stuff+ is a useful device – there’s merely an excessive amount of variability in breaking ball shapes and their differing effectiveness  to easily have a look at percentile rankings amongst the massive three metrics (velo, vertical break, horizontal break) and assume an correct mannequin. Stuff+ contextualizes when added carry is nice on a slider, and when try to be nudged in direction of a sinker as an alternative of a four-seamer. 


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