Pitcher Launch Angles And Home Run Rates

Some time ago I went through my database searching for batted balls that produce the greatest offensive benefit. I settled on a range of vertical launch angles between 21 and 36 degrees. This range of angles accounts for the majority of home runs and extra base hits, and are generally among the most valuable batted balls.

Balls hit between 21 and 36°
BIP H 1B 2B 3B HR SF
Stats 88200 35672 8438 8330 1446 17458 2406
% of Total 19.5% 22.5% 8.2% 26.2% 41.5% 84.5% 50.7%
AVG SLG BABIP wOBA
.416 1.158 .258 .632
All BIP with a measured Exit Velocity.
This excludes roughly 15% of BIP from analysis

These are the most valuable balls, and this is, generally speaking you want to see batters maxing out balls on these angles and pitchers minimizing them. In the traditional sense, this range encompasses “fly balls”, as you would see reported on Fangraphs (FB%), but some sources consider balls hit between 20 and 25 degrees to be line drives. Either way, this is an important range. This isn’t ground breaking material, but you may not be familiar with it being described in terms of angles.

We know home run rate went up dramatically in 2016, at least in part due to an increased average exit velocity. However, this home run surge took place almost entirely for balls with a launch angle between 25 and 36 degrees. Balls hit above and below this launch window saw little to no increase. Alan Nathan wrote a relevant article which I encourage you to read.

Going into 2017 it is nearly impossible to tell for sure whether the home run rates will remain steady, revert back to 2015 levels, or continue to increase. My gut tells me it will either remain the same or increase. You may feel otherwise. Either way, you may want to use this launch angle information to your benefit. Please note that the relationships I am referring to here are pretty weak, we’re talking about R squared values hovering around .180 and .200, so take this with a grain of salt.

I went through and calculated the change in home run rates hit between these angles for each pitcher. Please note, these home run rates represent only balls hit between these particular launch angles,  25-36°, so these rates should be significantly higher than the pitcher’s overall home run rate, which is diluted by other, less valuable launch angles. In fact, going forward, you may want to use these sorts of numbers in place of HR/FB, but that is another topic entirely.

Let’s start with the pitchers who saw the largest increases in home run rates.  Note that for the purposes here I am limiting the list to guys who gave up at least 50 BIP on these launch angles in both 2015 and 2016. This is a reasonably high bar that eliminates all relief pitchers and focuses instead on starting pitching.

Increased Home Run Rates On 25-36° Launch Angle
Name EV 15 HR% 15 EV 16 HR% 16 ΔHR%
Zack Greinke 87.4 11.6% 90.6 27.5% 15.9%
Justin Verlander 85.3 12.3% 90.3 26.0% 13.7%
Francisco Liriano 86.3 13.2% 90.2 25.9% 12.7%
Kyle Gibson 89.7 16.4% 91.4 28.8% 12.5%
Chris Archer 88.9 14.3% 93.3 25.4% 11.1%
Anthony DeSclafani 89.6 10.3% 89.0 21.2% 10.9%
Jose Quintana 86.2 9.0% 87.7 18.2% 9.2%
J. A. Happ 89.2 16.2% 91.7 24.6% 8.4%
Jon Lester 85.9 13.6% 87.4 21.6% 8.0%
Michael Pineda 92.2 22.0% 93.4 29.7% 7.7%
Minimum 50 Balls Hit between 25 and 36° in Both 2015 and 2016

Many of these guys are relevant to fantasy baseball, and the list consists of five of the top thirty pitchers according to NFBC ADP. There may be many potential explanations for increased home run rates, and these batted ball angles definitely do not tell the full story here, but take a look at the increases in Exit Velocities. Archer +4, Greinke + 3, Verlander +5 (!!!), Liriano +4.

In addition to exit velocity increases, many of these guys also simply gave up more balls on these crucial angles as a proportion of total BIP.  Greinke +4%, Liriano +2%, Gibson +2%, Archer +3%, deSclafini +2%, Pineda +3%.

We’re entering a season where the home run environment is a total unknown. In the past three years we have had one of the lowest home run environments in recent history followed by a pretty average year, and then one of the most prolific home run seasons since the end of the steroid era.  What do you make of that?  Nobody has an answer, it is truly bizarre.

Some people are looking at these pitchers and assuming the increased home run rate was a fluke, which is certainly possible. Maybe it represents a new normal, also possible. However, for the guys who gave up more balls on these angles, and higher exit velocities on those balls, you will want to proceed with caution.

If you feel the home run surge will reverse, then these are certainly the types of pitchers you may want to covet. Perhaps not these particular guys, since their ADP hasn’t been affected much, but perhaps guy like Josh Tomlin, Jeremy Hellickson, or Carlos Rodon who each suffered similarly from increased power on these particular launch angles.

Alternatively, you may want to look towards the guys who suppressed power on these particular launch angles.

Decreased Home Run Rates On 25-36° Launch Angle
name EV 15 HR% 15 EV 16 HR% 16 ΔHR%
Julio Teheran 92.0 21.9% 90.6 12.3% -9.6%
Corey Kluber 89.9 17.6% 86.8 11.1% -6.5%
Matt Shoemaker 91.0 30.4% 90.3 24.1% -6.2%
Trevor Bauer 89.0 23.3% 90.7 18.5% -4.8%
Masahiro Tanaka 91.8 27.6% 89.8 24.6% -3.0%
Johnny Cueto 86.4 19.0% 88.4 16.1% -2.9%
Chris Tillman 89.7 14.5% 89.7 12.0% -2.5%
Michael Wacha 89.6 24.1% 89.0 21.8% -2.3%
Yordano Ventura 90.7 25.9% 89.8 25.5% -0.4%
Mike Leake 91.6 19.7% 91.9 19.4% -0.3%
Minimum 50 Balls Hit between 25 and 36° in Both 2015 and 2016

(I’m pleasantly surprised with the average ADP of these two lists of pitchers, usually I accidentally include a bunch of marginal players.)

Anyways, Tanaka sticks out to me on this list. The guy is about two and a half years removed from a partially torn UCL, which he opted not to have surgery on. In 2015 he had a pretty good year, but in 2016 he went back to being a dominant ace. Part of his dominance is controlling these ideal launch angles/velocity combinations.

He gives up a fair number of balls between 25 and 36 degrees, don’t get me wrong, but the majority of them have an exit velocity around 90 mph or lower, which dramatically cuts into their home run threat. Tanaka gives up plenty of high velocity balls, too, but the majority have a launch angle closer to 10 degrees. As a result, he can control the other team’s power threats, and navigate his way through not only a home run friendly American League East, but one of the most home run happy seasons in recent history.  And he lowered his home run rate along the way!

Ground ball pitcher’s don’t necessarily give up fewer hard hit balls on these angles. Look at Tanaka’s teammate, Michael Pineda.  He was ranked 32nd in GB/FB rate (min 150IP)—in addition to substantially increasing his SwStrk%—but still gave up more home runs. You can blame Pineda’s struggles on a relatively weak fastball, but the damage speaks for itself.

Similarly, Lester and Archer both had very good ground ball rates, and both gave up more home runs.

Inducing a lot of ground balls isn’t quite enough to avoid these big hits. There is more to it than that. Maybe some of it is luck, I don’t know. I don’t have the answer, I can only point to these (relatively weak) correlations and offer suggestions.

If you think the home run rate will return to normal, maybe pick up a few of the guys who suffered disproportionately on these types of batted balls.  If you think the increased home run rates will continue into next year, you might want target guys who suppressed power numbers on these particular launch angles.

If you would like to see the full spreadsheet, containing data for 263 pitchers, click here.





Andrew Perpetua is the creator of CitiFieldHR.com and xStats.org, and plays around with Statcast data for fun. Follow him on Twitter @AndrewPerpetua.

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VottomanEmpiremember
5 years ago

Interesting post! A thought and a question:

1) Regarding the GB pitchers not being safe – this seems to line up with findings that fly ball hitters do BETTER against ground ball pitchers, and vice versa.

2) Whichever assumption I make about the overall home run environment, doesn’t my behavior also hinge on whether last year’s ideal launch angle hard contact movers made SUSTAINABLE changes? Tanaka made improvements in, essentially, managing quality of contact within dangerous launch angles, while Archer did the opposite. What feels like it’s missing is an analysis of whether these rates are generally sticky from year to year or fluctuate like BABIP, and whether these changes in outcomes are derived from meaningful and predictive changes in process.