The launch angle revolution is the anti-thesis to Eric Hosmer’s existence.
From 2011 to 2019, Eric Hosmer hit a lot of ground-balls. That's not exactly what you want to see from a first baseman playing on a contending team. As baseball has embraced the launch angle revolution, Hosmer shifted towards a ground-ball heavy approach.
Playing in the little league stadium that is Petco Park did nothing to avail his swing issues. During his time with the Padres, his ground-ball rate has increased five percentage points.
Then 2020 hit.
2020 has been a crazy year, but Hosmer's altered batted-ball profile added a new twist that literally no one expected. If it's really an unprecedented year, let's really get crazy. It's not as if we've had enough farcical things on our plate already.
Hosmer's ground-ball troubles have been well-documented. But this season, he has fully embraced the fly-ball revolution and his offensive production has swelled as a result.
In 29 contests this season, his ground-ball rate sits at 47.3 percent, seven percent below his career average. His production has behooved from his altered approach; he's currently running a .286/.344/.554 line with eight homers. If I extrapolated his current barrels rate over a normal 162 game season, his 61 barrels would represent a career-high by 26.
His career renaissance can be attributed to him seeking out better pitches to hit. As Fangraphs' Jake Malihot explored here, Hosmer is focusing in on fastballs, while laying off breaking pitches. Since he's now swinging at more optimal pitches, he's able to drive them.
All of his offensive metrics, including wOBA, xwOBA, and exit velocity, have trended the right way. It's worth noting, too, that his 37.2 Sweet Spot% is ten percentage points higher than his career average.
Along with improved pitch selection, he's also increased his average launch angle in order to augment his overall offensive package.
From 2015 to 2019, his launch angle sat at three degrees; in 2020, it's nine degrees.
There's plenty of evidence that proves his approach is working. Just take a look at this.
https://twitter.com/betonline_ag/status/1300159783320858626
and this.
https://twitter.com/jgroc/status/1301376506804023301
I never thought I'd see Eric Hosmer on pace for 44 home runs during a 162-game season, but 2020 is all full of sorts of surprises. That's exactly the production you want to see from your 144 million dollar man.
His Baseball Savant page is 2020's version of "Dogs Playing Pokers". It's just beautiful to gaze at. In both images, there's just so much red, with limited blue hues to be found.
Fellow contributor, Chase Seibold, touched upon this idea last week, noting that many of the Padres' other stars, including MVP candidate Fernando Tatis Jr, have also increased their launch angles.
Unfortunately for San Diego, Hosmer's production might be a mirage. Sure, he's now hitting tons of balls in the air, but this exact approach may not be sustainable in the long-term.
For those unfamiliar with the following terms, here's a quick primer.
Vertical Bat Angle (VBA) is the steepness of the barrel at the point it makes contact with the pitch. For those still confused, here's a fantastic visual.
https://twitter.com/epsteinhitting/status/1186830269988233217
An increased VBA usually produces an increased launch angle, which appears to be one of the changes that Hosmer's implemented this season.
Launch Angle Tightness (SDLA) is the distribution of a player's launch angles. Although SDLA sounds more like a stock ticker, I can promise it's a baseball metric.
A higher SDLA is promising because it correlates to a higher BABIP and better contact quality. (H/T to Fangraphs' Alex Chamberlain)
Hosmer's a strange case. Usually, players who have high VBAs have corresponding SDLA's, but as we can see from this tweet, Hosmer's an anomaly.
https://twitter.com/SwingGraphs/status/1298266219598888962
Props to Hosmer for increasing both his launch angle and VBA this year, but that's only one part of this increasingly-confusing puzzle.
To analyze Hosmer's launch angle tightness (SDLA), I created a histogram that visualized his launch angle distribution.
Thanks to additional research by Chamberlain, we know that the optimal launch angle for a batter is 19˚. So if Hosmer's breakout is legitimate, there should be plenty of BBE's located near 19 degrees.
For the "Wizard of Hoz", there's good news and bad news.
The histogram indicates that he has 13 BBEs apiece in both the 15˚ to 25˚ and the 5˚ to 15˚ buckets. That certainly bodes well for Hosmer's future production. In 2020, BBEs located in these buckets have produced a .725 wOBA and .596 wOBA, respectively.
On the down side, there's plenty of BBEs that are located in the buckets with negative launch angles, indicating that Hosmer's ground-ball tendencies aren't past him. A quick glance at his 2020 batted-ball profile confirms this theory. Although his fly-ball rate has certainly increased, his ground-ball percentage is still higher than the MLB average.
Many of his BBEs remain eons away from the ideal 19˚ mark. 13 of his batted balls fall in the -15˚ to -5˚ range, a span which corresponds to a league-wide wOBA of .159 this season. Hosmer has a .522 wOBA on these BBEs.
There are two inferences that you can deduct from this data.
Considering he ranks in the 20th percentile in sprint speed, I'm of the mindset that it's the former option.
Furthermore, Hosmer's BBE histogram doesn't resemble a bell-shaped one you would hope to see from a launch angle tightness graph.
For reference, Devan Fink of Fangraphs analyzed Mike Trout's launch angle distribution and found that his graph is in the shape of a normal distribution, with his wOBA peaking in the 20˚ to 30˚ bucket.
Of course this is simply the launch angle tendencies of one hitter, but it's always a good rule of thumb to follow the GOAT.
Hosmer's previous SDLAs have mirrored bell-shaped curves. However, in 2020, his distribution looks similar to a binomial curve, with peaks around -15˚ to -5˚ and 5˚ to 25˚.
If Hosmer really wants to enter the echelon of baseball's top sluggers, he needs to smooth out his SDLA and have more BBEs centered around the 19˚ mark. If that fails to occur, Hosmer's offensive performance could be nothing more than a one-year irregularity.
There seems to be legitimate improvements that Eric Hosmer has made this season, but I'm unsure how much of it will stick beyond this 60-game sprint.