Whether you’re a Cubs fan or not, if you’ve been paying much attention to their off-season thus far you’ve probably been met with some confusion and disappointment. Sure, if you’re not particularly fond of the Cubs, you’re probably not complaining that they’re beginning the process of tearing down the roster, but one of baseball’s biggest market teams turning away from contending is never good for the sport overall. A lot of the team’s moves to acquire younger talent make sense for a franchise that’s hoping to build up for the future rather than the present, even if the prospect return in the Yu Darvish trade was notably very young. The one piece that doesn’t necessarily make sense in the return for Darvish, though, is 27 year old starting pitcher Zach Davies. Sure, he’s six years younger than Darvish, but he’s currently set to pitch just one season with the Cubs before becoming a free agent upon the conclusion of the 2021 season. That’s likely not the most confounding part of the acquisition, though: with the acquisition of Davies, a soft-throwing righty, three of the pitchers in the Cubs rotation will be very similar, as the 2020 rotation already featured Kyle Hendricks and Alec Mills. Indeed, Mills’s sinker is the only pitch that any of the three throws that averages even 90 MPH, and none of them ever throw any faster than 93 MPH. So that leads to several questions on the minds of many: how successful will these three pitchers be in the same rotation together? The bigger question: are they too similar to succeed together?
I’m going to attempt to answer these questions here by analyzing three major components of each pitcher and comparing them:
- Their pitch arsenals: What pitches does each pitcher throw? How similar are these pitches in terms of speed, spin rate, etc?
- Their release points: Might these pitchers be distinct enough in release point to make up for a similarity in fastball velocity?
- Approach/Results: How do these pitchers use the pitches they have, and what kind of results to they get from each pitch? Do these pitchers typically attack hitters in the same way, or do they have distinct approaches that will differentiate them enough to remain effective?
This will be fairly in-depth on an individual level for each pitcher, but the primary focus of this article will be comparisons between the three pitchers. I wrote an in-depth analysis of Mills in September that you can read here.
First, I’ll be analyzing their pitch arsenals, which are fairly similar in terms of the pitches they throw (pitch data via Baseballsavant.com) Hendricks and Davies both work with four pitches, while Mills has five distinct pitches that he throws. Here is a list of the pitches that each throws, along with the average velocity and spin rate of each pitch and how frequently he threw each pitch, all in 2020.
One thing that jumps out at first glance is that all three pitchers feature three of the same offerings: a sinker, a changeup, and a curveball. Moreover, all three use their sinker more than any other pitch they throw. All three come in near the bottom of MLB in fastball velocity and fastball spin, which for Hendricks and Mills also includes data from their 4-seam fastballs.
That comprises the entirety of Hendricks’s pitch arsenal; Davies adds a cutter; and Mills supplements his with a slider. There are a couple of nuances here, including some slight differences in velocity and spin between the pitches that each pitcher throws, but all three of them use a fastball-changeup combination for at least three-quarters of all pitches they throw. So yes, on face their pitch arsenals are indeed very similar. Still, there are ways that they differentiate themselves, and there are some notable differences between their pitches.
Foremost among these differences are the two breaking balls that Mills offers. While his fastballs are the highest velocity pitches of the bunch, there is nothing too special about those pitches or his changeup. His curveball, though, is very slow. In this article about the slowest strikeout pitches of the 2020 season, only Zack Greinke and a pair of position players managed slower strikeout pitches than Mills’s curveball in 2020. The slow speed of the pitch allows it plenty of time to break vertically, and it breaks a staggering 73 inches in the vertical direction in addition to having 13 inches of horizontal break relative to the MLB averages of 53 and 9 inches, respectively. This slow curve differentiates Mills’s arsenal quite a bit, serving as an offering that yielded a wOBA of just .209 in 2020. Here are a couple of Mills’s curves from his 2020 no-hitter which show both the pitch’s extreme vertical break as well as its horizontal break in towards the left-handed hitters:
Mills’s other breaking ball, his slider, is also a distinct difference between him and his rotation-mates, as neither of them throws a slider and it is both Mills’s fastest-spinning pitch and that which gives the most horizontal break. MLB sliders average roughly 6 inches of horizontal movement; Mills’s slider averages 17 inches of horizontal movement. In addition, it also drops 11 inches more than league average. Here’s a pair of Mills sliders that show off the pitch’s extreme horizontal movement:
While Davies also adds a unique pitch to the fastball-changeup-curveball mix, his cutter isn’t his most distinct pitch. His changeup is his specialty pitch, and while it doesn’t look all too special if you’re referring to the data above, there’s one characteristic of his changeup that makes it far more lethal than it seems: the pitch has a 99% active spin rate. A pitch’s active spin rate is a representation of how much of its spin is actually contributing to movement, and there are very few pitches in baseball with an active spin rate as high as Davies’s changeup. This makes it the most lethal pitch in his arsenal by far and explains why he has used the pitch more every year since 2018. Here’s a changeup that Davies threw for a swinging strike in 2020:
Hendricks doesn’t necessarily differentiate himself from the other two with his arsenal, but as we’ll see momentarily his approach is so excellent he hasn’t needed to. Before we move onto approaches, let’s first check out the release points of these three pitchers.
There’s not quite as much to discuss here, but the main question is this: are these three pitchers distinct in their release points such that their pitches will look different to opposing hitters? Even if they have very similar stuff, which they do, a significant enough difference in release point will make their pitches look more distinct from one another, allowing for them to be more successful. I don’t know of any information that would indicate any causal relationship between release point and ERA (or any similar indicator of success), nor is there information on whether a variety of release points has any causal relationship with the overall success of a pitching staff. There is concrete data on the average release height of each pitcher, though:
Hendricks: 6.1 ft above the ground
Mills: 5.7 ft above the ground
Davies: 5.5 ft above the ground
On average, there is a 2-3 inch difference in height between the release points of Davies and Mills, and another 4-5 inch difference between Mills and Hendricks. While this doesn’t make all the difference, it is one more factor that can differentiate these three pitchers and indicate that they’re not so similar that they cannot succeed together. Their release points can be seen in these visualizations from MLB’s Baseballsavant:
There is also a horizontal component of release point, and this is also promising: while Mills’s release point is in between those of Hendricks and Davies, it is also wider, which will differentiate it more. Again, it’s difficult to say how much of a difference this will make, but with three pitchers who sport similar stuff, a variety of release points is one factor that will help the Cubs rotation provide different looks to hitters.
These three pitchers do have similar approaches, which is not all that surprising considering the similarities in their pitch arsenals. However, there are differences in how they approach hitters and these mean that each pitcher has found success in a slightly different manner. I’ll be analyzing here how each pitcher’s approach has contributed to his success, as well as some ways that their differences could be useful in 2021.
One of the main components of approach is where each pitcher tends to throw each pitch that he offers. Before looking at individual pitches, information can be ascertained from the following graphs, which demonstrate where each pitcher threw his pitches in 2020
These images are from the perspective of the catcher. There is one obvious similarity here: all three pitchers tend to target the lower outside edges of the strike zone, with the lower right corner being the most frequently targeted because right handed batters are more common. Moreover, these pitchers live on the edges of the strike zone. The league average rate for pitches thrown on the edge of the strike zone is 39%. 45.9% of Hendricks’s pitches, 46.0% of Davies’s, and 44.6% of Mills’s were thrown on the edge of the strike zone in 2020. So, in general, this gives us a lot of similarities between the three:
- They all thrive on a very similar fastball-changeup mix
- They all target the lower outside corners of the zone most frequently
- They hit the edges of the zone with above-average precision
The first two points aren’t particularly unique, but these similarities speak to what is necessary to find success without velocity, as these are the things that all three pitchers have in common.
With this general similarity in approach in mind, we can look at how each pitcher’s approach differs from the others to see where they’re unique enough to generate success.
Hendricks has come to thrive on incredible precision when he pitches, a fact which is not new to anyone who watches him pitch. His four pitch mix features nothing eye-popping, but he gets some of the best results of any pitcher in baseball because of how well his pitches play off of one another. Take, for example, this overlay of his changeup and sinker from 2018, where he places the two pitches which are 9 MPH apart in almost the exact same spot:
Still, all three of these pitchers have good command; that’s why they’re able to succeed at all without the velocity of most of their counterparts. Hendricks has one notable difference from Davies and Mills that’s visible in the above graphs: He purposely targets the upper inside portion of the zone with his fastballs as a means of generating weak contact in the air. He uses his sinker to target righties up and in, and his four-seamer to target lefties in the same way. In general, his fastballs are thrown across the entire strike zone, while he throws his changeup and curveball down in the zone.
Hendricks profiles as a fly ball pitcher thanks in part to his intentional outcome of inducing weak contact on fastballs up and inside to hitters.
With all of this in mind, Hendricks’s pitch selection for each pitch in the count makes sense:
Hendricks is comfortable using his sinker in every count as a pitch that generally can induce low quality contact. Either he goes high and inside with it against righties in order to generate weak contact in the air, or it functions as a traditional sinker and generates contact on the ground. The pitch has the lowest average launch angle of all of Hendricks’s offerings, with hitters only managing a 7 degree launch angle on average against the pitch. Still, it yields the most contact of any pitch Hendricks throws, so he tends to shy away from it in hitter’s counts and later in plate appearances. He uses his four-seam fastball to supplement his sinker and make it more difficult to pick up on, favoring the four-seamer as he gets into deeper counts. As such, it functions as his best strikeout pitch with a 25% putaway rate.
Finally, he has his changeup and curveball, which play off of his fastballs to induce much weaker contact and more whiffs. While his fastballs have a whiff rate of roughly 20%, his changeup and curveball both have whiff percentages around 30%. In addition, the average exit velocity of each pitch barely eclipses 80 MPH, resulting in a wOBA of .241 against Hendricks’s changeup and .144 against his curveball in 2020.
Ultimately, Hendricks’s primary means of success in 2020 was in his extreme ability to limit walks. He was tied for the lowest BB% in baseball, allowing a free pass on just 2.5% of plate appearances and averaging less than one walk per nine innings pitched. This elite command paired with his ability to limit contact (fourth lowest average exit velocity allowed among qualified starters in 2020) and get a few strikeouts makes Hendricks an efficient and successful pitcher.
While Davies and Hendricks throw a very similar proportion of their pitches around the edge of the strike zone, Davies throws far fewer pitches in the strike zone than Hendricks: Hendricks hits the strike zone 51.9% of the time, while Davies hits the zone just 42.7% of the time (49.9% is league average). Ultimately, Davies relies heavily on the swing and miss potential of his changeup that I mentioned previously, and he lives in the lower half of the strike zone to a far greater extent than Hendricks, using his sinker in the lower half of the zone either to set up his changeup or induce weak contact on its own. Here is the same pitch selection graph for Davies in 2020:
Davies primarily uses his sinker in hitter’s counts, switching to his changeup when he is ahead in the count and using his cutter once in a while in most counts to keep the hitter guessing. This changeup usage makes sense, as Davies allowed just a .220 wOBA with the pitch in 2020. He generally used his curveball on the first pitch of the plate appearance in 2020 without throwing it much in any other count. Davies throws his sinker for strikes 47% of the time, more than his other pitches. In contrast, his changeup hits the strike zone only 39% of the time, as he generates more swings and misses with the pitch even when he misses the zone. While Hendricks follows a similar pattern of throwing his fastballs for strikes and switching to a changeup to finish plate appearances, Davies is notably different from Hendricks both in terms of how his changeup misses bats and how he has a lower release point.
Ultimately, Davies has yielded above average results throughout his career without ever being stellar. He has a higher strikeout rate than Hendricks but also walks roughly three times as many batters, which speaks more to how incredibly low Hendricks’s walk rate is. While the two have similar home run rates, Davies allows more hard contact and more contact in the air, though he still comes in at the 64th percentile of average exit velocity allowed. While Davies did not get hit too hard on average, he was in the 14th percentile of barrel rate, indicating that he allows a relatively high quality of well-hit balls. This should still be okay in Wrigley Field, though, which is a relatively low-HR environment.
Mills, meanwhile, has… a very similar approach as well, although his pitch usage is not quite as dependent on the ball-strike count of the plate appearance. Mills’s pitch location chart above looks almost identical to Davies’s, with most of his work coming on the lower corners of the strike zone. Here is Mills’s pitch selection graph by count:
Mills can throw most of his pitches in any given count, reverting mainly to his fastballs as he gets behind in the count and as plate appearances progress. This is different from Davies and Hendricks, as they move away from their fastballs in 2-2 and 3-2 counts; Mills favors his fastballs in these counts. Ultimately, though, one change that he may look to make heading into a new season is moving away from the use of his four-seamer when possible, as it was easily his hardest-hit pitch in 2020. Increasing the usage of both his unique curveball and his slider, which neither of Hendricks nor Davies throws, may be effective for Mills as a means of diversifying himself as well as utilizing his best pitches to their maximum potential. Still, Mills is not currently a high strikeout pitcher, nor should he strive to be. His 7.6% SwStr rate was the second-lowest among qualified Major League starters in 2020, and he generally doesn’t have the stuff to miss bats.
Mills doesn’t get excellent results in general, but he is still a good pitcher who can provide quality innings. Mills survives by inducing weak contact rates, but his strikeout rates are the lowest of the bunch while also allowing more home runs and walks, yielding results that are much closer to league average than those of Hendricks or Davies. Still, the proper usage of his pitch arsenal will allow Mills to maintain his status as a valuable inning-eating starter for the Cubs.
Ultimately, these are three very similar starting pitchers, and there isn’t much information out there that will tell you otherwise. However, they’re not identical, and their differences are distinct and important. Hendricks is uniquely precise with his command, Davies has a uniquely effective changeup, and Mills offers a unique pitch mix as well as a wider release point. While all of them live on the same three pitch mix, there’s no reason to believe that their presence in the same rotation will seriously impact their effectiveness as pitchers. Indeed, these low-velocity right handers seem to be a place where the Cubs believe they have found value that others have overlooked, and they do indeed have three above-average starting pitchers, with Hendricks being a top 20 starter in baseball, as a result. The extent to which these three pitchers will succeed in 2021 remains to be seen, but it is known that all three have found unique ways to tap into similar means to success in Major League Baseball, and there’s no reason to believe that that will be any different moving forward.
All visuals courtesy of baseballsavant.com. Data courtesy of Baseballsavant.com and FanGraphs.