Looking at the velocity gap between offspeed pitches and fastball

Ever wonder how Chris Archer’s slider is so good? How Clayton Kershaw’s curveball is so devastating? Why Cole Hamels is able to use his changeup so effectively? Those are just a few examples, but when you think of great pitchers they are often connected with good off-speed offerings. Using pitch type linear weights, this isn’t all too surprising. When quantifying the effectiveness of pitches, there are a couple of different methods you can use. Pitch type linear weights certainly aren’t the best possible option, but they do offer a look of how many runs a certain pitch is worth on average. Since the beginning of the PITCHf/x era, which is from 2007 onward, here is how all fastballs, sliders, cutters, curveballs, and changeups leaguewide compare:

Pitch Type	FB	SL	CT	CB	CH
Total	-530.8	484.2	82.5	-10.8	15.1
Per 100 Pitches	-0.13	0.47	0.26	-0.01	0.02

Now the major caveat here is that pitch type linear weights don’t account for pitch sequencing, and can occasionally be inaccurate when a pitch is used a bunch. The latter is covered well here by our very own Henry Druschel, and is probably a leading reason as to why fastballs appear to rate so poorly, while the former can be understood when thinking about how pitches work together to get an end result. Say you are a pitcher and you’re up 0-2, and you throw a fastball up in order to change the hitters’ eye level. The batter doesn’t chase the pitch, and the count moves to 1-2. You then follow that up with a curveball in the dirt, which the batter swings and misses on. The fastball gets no credit in terms of positive run expectancy tacked on because, in the eyes of pitch type linear weights, it was just a ball that increased the potential of a run being scored. The curveball is the pure recipient of the success.

That doesn’t mean there is no validity in pitch type linear weights, of course, but they should be used more as one piece of the puzzle in deciding how effective certain pitches are. Now that I get off of my soapbox, what makes an offspeed pitch so effective? Initially you might point to the variation of movement these pitches typically offer when compared to fastballs, but what about velocity?

I’m not going to settle the argument of what makes one pitch better than another, but I am here to discuss how velocity differences, when compared to fastballs, play a role in offspeed pitches. Consider Rangers’ co-ace Yu Darvish, whose heater sits at 93 mph (at times touching the high 90s). This is not unusual in an era of fastball velocity, but made even more striking when he also throws an 89 mph cutter, an 88 mph splitter, an 86 mph changeup, an 81 mph slider, a 78 mph curveball, and a 69 mph slow curveball (that has been recorded as slow as 56 mph). This gives Darvish an average range of 24 mph between his fastest and slowest pitches, and with his plethora of offspeed offerings, he is capable of throwing a quality pitch at almost any velocity within that range. Factor in his peak fastball velocity and his lowest slow curve velocity, and Darvish has thrown anywhere between 56 and 98 mph – a whopping 42 mph range.

Movement aside, it is very difficult for hitters to be prepared to hit pitches coming in at such different speeds. There is no good way to prepare for 98 mph at the letters while also staying ready to hit the 56 mph slow curve, the 81 mph slider, and the 86 mph changeup at the same time. Pre-injury, it was no surprise that Darvish was one of the most effective pitchers in the league, and his ability to change speeds has certainly contributed to that success. The question, though, is how do other pitchers in Major League Baseball vary their speeds, and is there a close-knit difference in offspeed velocity when compared to a pitchers’ fastball? After looking through the PITCHf/x data from 2015, here’s how the four aforementioned pitches vary from their pitchers’ fastballs velocity-wise on average.

Slider

Average Velocity Difference: 7.7 mph

Standard Deviation: 2.2 mph

Maximum: 15.6 mph – Chris Sale

Minimum: 3.2 mph – Yovani Gallardo

Range: 12.4 mph

The slider features the largest range between maximum velocity difference and minimum velocity difference of any pitch in this data set. Yovani Gallardo’s slider features the velocity of a cutter, but the movement of a slider—a contributing factor to his transformation into a ground ball specialist. On the other hand, Chris Sale features a 15.6 mph velocity difference, led all left-handers in horizontal slider movement, and ranks sixth among all pitchers in vertical slider movement. Generally speaking, his slider is well known to be what we often refer to as "filthy". Chris Archer, who is the owner of another great slider, features a standard 7.3 mph velocity difference from the fastball and an above average 4.2 inches of horizontal movement.

Another version of the pitch increasing in popularity is the Warthen slider, named after and primarily taught by Mets’ pitching coach Dan Warthen. As Eno Sarris explained at FanGraphs, the Warthen slider is thrown harder, and with less spin than the average slider. The relatively minimal pronation necessary to throw the pitch, along with the Warthen slider’s ability to stay on fastball trajectory longer than others and added deception, helps the small but quick late break maintain effectiveness.

Curveball

Average Velocity Difference: 14.2 mph

Standard Deviation: 2.7 mph

Maximum: 20.4 mph – Mike Pelfrey

Minimum: 8.8 mph – Alex Wood

Range: 11.6 mph

Coming in, on average, at around 14 mph slower than a fastball, curveballs have the largest average velocity gap by almost five mph. Interestingly, the pitch is known for beating hitters with movement and not velocity, although the slow curveballs of Darvish and Mike Pelfrey provide exceptions. With the rise of the slider and cutter, pitches that stay on fastball plane longer and are consequently often more difficult to identify than the curveball, the curveball seems to be on the decline. In spite of this, it seems premature to forecast the demise of old Uncle Charlie while watching Clayton Kershaw make batter after batter look foolish waving at his deuce.

That being said, not all curveballs are intended to fool hitters with velocity. Some of the best in the league are thrown relatively hard and with a small but sharp break. Alex Wood is the leader in the curveball velocity department, while Sonny Gray and Felix Hernandez are others certainly trying to fool hitters with the sharpness of the break as opposed to the speed of the pitch. It is all about finding the perfect balance between velocity and movement, and this balance helps create the deception you often hear analysts talk about.

Changeup

Average Velocity Difference: 7.5 mph

Standard Deviation: 1.8 mph

Maximum: 15.3 mph – Scott Kazmir

Minimum: 3.3 mph – Zack Greinke

Range: 12 mph

Like the curveball, changeups can win on both velocity and movement. Zack Greinke and Felix Hernandez are among the main contributors to the rise of the fast changeup. Greinke has seen success with his 3.3 mph gap, a contributing factor into his league-best wCH of over 20 runs, while the latter has earned a deserving reputation for possessing one of the most lethal changes in the game. We have all had the pleasure of bearing witness to King Felix’s change-up.

On the other, more traditional side, there is a pitch intended to win with the deception that stems from a more significant velocity difference. Movement on the pitch is a nice bonus, but for a slower changeup, deception and velocity are essential. Cole Hamels and his 8.2 mph difference set the standard for the offering, while others like Scott Kazmir see an even larger gap. There is no single velocity ideal for a changeup and, despite its’ origins as a pitch that wins with a large velocity difference, the modern changeup relies on movement and deception as much as a lack of speed.

Cutter

Average Velocity Difference: 3.48 mph

Standard Deviation: 1.67 mph

Maximum: 6.8 mph – Shelby Miller

Minimum: 0.6 mph – Kyle Hendricks

Range: 6.2 mph

As cutters are basically sliders that break less, yet are thrown harder, it shouldn’t be too surprising to see an average velocity not all that dissimilar from a pitchers’ given average fastball. Like the slider, there are many ways for a cutter to be successful. The horizontal movement Shelby Miller features on his cutter isn’t really anything to write home about, however his 6.8 mph velocity difference and above average vertical drop helped it become his best pitch last season. On the flip side, Kyle Hendricks featured little movement or velocity difference on the offering, and hence his cutter was a pitch that was rated poorly by linear weights.

So, when looking for the perfect velocity for an offspeed pitch, what have we learned? Well, that there really isn’t one.The question "Coach, how hard should I throw my offspeed pitch?" is one without a clear answer other than "Find a speed that works." Quantifying a good pitch requires far more than a radar gun reading, and although velocity is the foundation of all pitches, it is foolish to make any assertions that certain pitch must be within a certain velocity range to be successful.

How many coaches would pull a 15-year-old Felix Hernandez aside and tell him that his changeup will never work unless he subtracts more velocity? My guess is that too many would step in, at least until they saw him throw the pitch with great success in the game. Tweaking the velocity of offspeed pitches can be helpful, but this analysis shows that any tweaking must not conform to any arbitrary standards of offspeed velocity, as no such standards exist.

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Shawn Brody is a contributor for Beyond the Box Score as well as a sophomore pitcher at Howard Payne University majoring in Business Management. If you would like to get a hold of him, please feel free to email him at Shawnbrody9@gmail.com or follow him on Twitter @ShawnBrody.