RADIO
Welcome back to my series of posts where I take us through a standard fantasy baseball category, break it down statistically and then locate some targets for 2021 to help you out in that category. We've already examined how to get an advantage in batting average. Today we will talk about home runs. You can also read other articles in this series for my breakdowns of other later-round category targets series.
The question is, where do home runs come from? I had some theories in my head about this so I went to the data to test some of them out. I found a handful of statistics that had meaningful relationships with home runs. The most meaningful stat is, of course, plate appearances. The more a hitter comes to the plate, the higher chance a favorable outcome occurs.
So as not to rely too much on PA, I also used home run rate (plate appearances divided by home runs) instead of raw home run totals. Here are the results.
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Maximum Exit Velocity
I was super skeptical of maximum exit velocity the first time I heard it. Why would you want to look at just one single event rather than the whole picture? It didn't make sense! But then I came to the realization that maximum velocity is indicative of bat speed. Average exit velocity indicates this as well, but maximum does a better job. Some players simply are able to swing the bat harder than others, and that immediately raises their home run rates.
These plots look essentially the same and do not display that maximum works better than average, but in terms of correlations, the max value does beat out average pretty substantially (-.52 vs. -.33).
Looking at the maximum velocity leaders over the last three seasons isn't super helpful because it's mainly stud names, but here it goes anyway:
| Player | Max Velo | Avg Velo |
| Giancarlo Stanton | 121.7 | 92.5 |
| Gary Sanchez | 121.1 | 89.0 |
| Aaron Judge | 119.9 | 93.8 |
| Vladimir Guerrero Jr. | 118.9 | 87.7 |
| Pete Alonso | 118.4 | 88.7 |
| Daniel Palka | 118.4 | 91.5 |
| Aristides Aquino | 118.3 | 85.3 |
| Mike Trout | 118.0 | 89.8 |
| Christian Yelich | 117.9 | 91.4 |
| Jose Abreu | 117.9 | 90.4 |
Some names that are more interesting for our purposes that make the top 30:
Marcus Semien (117.5), Rowdy Tellez (117.4), Nomar Mazara (117.1), Rafael Devers (116.7), Avisail Garcia (116.7), Luis Robert (116.4), Josh Bell (116.2), Teoscar Hernandez (115.9)
Fly Ball Rate
A fly ball is classified as a ball hit between 25 and 50 degrees. That is where 82% of the home runs (excluding inside-the-parkers) of the last three years have been hit. The other 18% is made up of line drives (between 10 and 25 degrees).
Most fly balls don't go for home runs, so it's possible to have a high fly ball rate but still not hit many home runs, but almost all of the league's home run hitters have high fly ball rates.
Average Velocity On Fly Balls
This is a bit redundant, but it is important to note. How hard a hitter hits ground balls has no correlation with his home run rate (a coefficient of -.189), while the average velocity on fly balls has a strong correlation (-.552). This is not what I expected to see. I would have previously thought that there would be some relationship since a guy hitting the ball hard, even if it's on the ground, is obviously swinging a pretty quick bat. But if we look at the average velocity on ground balls leaderboard, names like Robinson Cano, Nick Markakis, Yulieski Gurriel, and Miguel Cabrera are all in the top 10 despite having below-average home run rates.
If we look at the guys with the highest average velocities on fly balls:
| Player | FB Avg Velo |
| Joey Gallo | 99.6 |
| Giancarlo Stanton | 98.7 |
| Miguel Sano | 98.4 |
| Nelson Cruz | 98.2 |
| Franmil Reyes | 97.7 |
| Christian Yelich | 97.3 |
| Aaron Judge | 97.0 |
| Juan Soto | 96.9 |
| Teoscar Hernandez | 96.7 |
| Eloy Jimenez | 96.7 |
One way ticket to JACKsonville, am I right?
Other interesting names:
Shohei Ohtani (96.3), Jorge Alfaro (96.1), C.J. Cron (95.9), Max Stassi (95.8), Daniel Palka, (95.8), Tommy Pham (95.2), Max Muncy (95.2), Danny Santana (95.0), Brandon Lowe (95.0), Chad Pinder (95.0)
And really, that is the end of the story. I checked whiff rate, pull rate, chase rate, and others and no other category really would make a predictive model any better than what we could do just by using the stats above.
Predictive Model
I ran the model and made predictions on what home run rates were "expected" for each player from 2018-2020. Here are the highest predictions it made along with what actually happened.
| Player | Predicted | Actual |
| Joey Gallo | 8.1 | 15.1 |
| Miguel Sano | 8.4 | 15.7 |
| Mike Trout | 9.9 | 13.9 |
| Teoscar Hernandez | 12.8 | 18.6 |
| Aaron Judge | 13.0 | 16.7 |
| Nelson Cruz | 13.3 | 13.9 |
| Gary Sanchez | 13.3 | 16.0 |
| Giancarlo Stanton | 13.5 | 19.2 |
| Adam Duvall | 13.5 | 18.6 |
| Pete Alonso | 14.4 | 13.4 |
| Yordan Alvarez | 14.8 | 13.4 |
| Ronald Acuna Jr. | 15.2 | 17.2 |
| Bryce Harper | 15.5 | 19.3 |
| Franmil Reyes | 15.7 | 17.3 |
| Jay Bruce | 15.7 | 19.0 |
If we look at the guys that the model thinks should have way more homers hit than they actually have, leaving the guys on the above list off for redundancy's sake, here are some names:
Matt Carpenter, Yolmer Sanchez, Joey Votto, Mallex Smith, Andrew Benintendi, Mike Zunino, Rhys Hoskins, Brandon Belt, Jackie Bradley Jr., David Fletcher, Ronald Acuna Jr.
HR Targets
Joey Gallo (OF, TEX), ADP 167: Holy cow, a "home run targets" article that recommends Joey Gallo! No one could have seen this coming! But look, I can't leave him off. He is the #1 rated home run hitter by this model and he's cheaper than ever before this year after a bad 2020 season. His 117.5 max velocity, 35.4% fly-ball rate, and 99.5 mph average velocity on fly balls are all near the top of the list. He is an awesome guy to scoop up for mid-round home run production, especially if you play in an on-base percentage league.
Miguel Sano (3B, MIN), ADP 188: Another "duh", but he's even cheaper than Gallo.
Teoscar Hernandez (OF, TOR), ADP 69: I suppose there are some playing time questions right now, but as long as he is in that lineup every day he should continue to hit the long ball. He has wicked bat speed (maximum velocity of 115.9), gets the ball in the air (31% fly-ball rate), and hits those balls hard (96.7 fly-ball velocity). The great 2020 season he had makes him a bit pricey, but he's worth a look even with the sixth round price tag.
Jay Bruce (OF, FA), ADP 743: This is only relevant if he signs with a team that has an open DH spot, but the guy has always hit homers at a high rate and he's still only 33 years old. He will be basically free in drafts no matter what happens, and he should be able to pop 30 homers if he can find his way to 500 plate appearances.
Hunter Renfroe (OF, BOS), ADP 457: Not sure if he will play every day in Boston, but he is an exciting power hitter especially given his new home ballpark. He has played his whole career in San Diego and Tampa Bay, two of the toughest parks to hit homers in, so Fenway makes him really interesting at this cost. He's homered once every 15.5 plate appearances in his career, well above the league average, and that should theoretically speed up even more now. With a maximum exit velocity of 114.1, a 29% fly-ball rate, and a 95.6 average launch velocity on fly-balls, he could easily be right with the league leaders in dingers if given the opportunity.
Franchy Cordero (OF, KC), ADP 405: Franchy has never seen more than 154 plate appearances in a Major League season, but he appears poised to crush that number this year. He's currently penciled in as a starting outfielder for the Royals. He has a maximum exit velocity of 116.9, and an average velocity on fly-balls of 97.3. The one thing missing is the fly ball rate, which has not been high for much of his career. A change in approach may be all he needs to become an easy 30 homer hitter, and he's another guy that is essentially free in drafts.
Sean Murphy (C, OAK), ADP 168: My typical approach with drafting catchers is to wait as long as possible and then take a guy that will at least hit a few homers. Murphy is a great candidate for that this year, as he projects to be the Athletics starter and hit somewhere near the middle of the order. He has an impressive PA/HR rate for his career of 18, and that is backed up by a 30% fly-ball rate and a really high average velocity on those fly-balls at 97.4.
Rhys Hoskins (1B, PHI), ADP 172: The price has just fallen so much since that rookie breakout, but Hoskins should continue to mash homers in between strikeouts. He has a really high 34% fly-ball rate with a strong max velo (112) and fly-ball velo (93.5).
Brandon Lowe (2B, TB), ADP 71: Not very cheap after his strong 2020 season, but the power is real. He has great bat speed (114.3 max velocity) and hits his fly-balls hard (95.0), but he doesn't hit a ton of them (28%). If he turns that up to 32% or so, he could be a 35+ homer guy.
C.J. Cron (1B, FA), ADP 328: Another guy we're waiting on as a free agent, but Cron has been one of the more prolific power hitters in the league in recent years when on the field. He has homered once every 18.7 plate appearances over the last three seasons, good for an easy 30+ homer pace over a full season. He is dirt cheap once again, but that ADP could bloat depending on where he signs and when.
Players to Avoid
Strictly speaking of players being drafted in the top 200 that the model does not expect to hit many home runs, and filtering out names that aren't interesting, here are some players that could fail to deliver high HR totals:
Alec Bohm (3B, PHI, ADP 101): I don't think the players who have taken a close look at Bohm would expect homers, but he does have some of that "prospect name value." However, he did not get the ball in the air hardly at all last year (15%), and his velocity maxed out at just 109.6.
Ryan Mountcastle (1B/3B, BAL, ADP 143): Same story with Bohm as a second-year player in 2021. Mountcastle did not hit fly-balls (21%) and did not show off great bat speed (108.2). There are many years ahead of these two guys now, but with the information we have right now we should not expect a surge of homers.
Whit Merrifield (2B/OF, KC, ADP 40): Yeah, you are not expecting home runs when drafting Merrifield, but you did get some last year surprisingly. This is a warning not to expect that again. Whit has a really low maximum velocity (106.4, and that's in a ton of plate appearances) and is an average fly ball hitter (24%).
Randy Arozarena (OF, TB, ADP 59): Admittedly this isn't fair because my study only included regular season data. But before the 2020 playoffs came around, Arozarena had posted just a 19% fly-ball rate. He does have pretty solid exit velocity numbers even in the regular season data, but there's reason for pause.
Luis Robert (OF, CHW, ADP 35): Guy murdered the ball last year, but still mainly hit grounders and line drives with a fly-ball rate of just 17.6%. Fly-ball rate is probably the easiest metric in this study to change, so I could be eating my words here, but it's worth noting that Robert may be more of a 25-homer guy than 35.
Other names to temper home run expectations on: Trent Grisham, Nick Solak, Trea Turner, Dylan Carlson, Ketel Marte, Carlos Correa, Max Kepler
That's it and that's all! Check back soon for more category targets.
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