Quick: what do Eric Hosmer, Sam Hilliard, Darin Ruf, and every pitcher in baseball have in common? You guessed it, none of them have hit a ground ball so far this season! Unsure on what exactly this means for Ruf’s future, but it is a potentially career-altering development for Hosmer. Since signing with the Padres in 2018, Hosmer has the highest GB% of all qualified players at 58.2%. Not to say a player cannot be successful hitting such a high rate of grounders, but its definitely more difficult. Here are all the players who had ground balls account for more than 50% of their balls in play over the last two seasons:
| Player | GB% | wRC+ |
|---|---|---|
| Eric Hosmer | 58.2 | 93 |
| Ian Desmond | 55.4 | 84 |
| Dee Gordon | 54.5 | 76 |
| Lorenzo Cain | 52.4 | 104 |
| Jonathan Villar | 51.8 | 101 |
| Jean Segura | 51.7 | 101 |
| Andrelton Simmons | 51.5 | 97 |
| Nomar Mazara | 51.2 | 95 |
| Tommy Pham | 51.0 | 125 |
| David Peralta | 50.8 | 121 |
| Starling Marte | 50.6 | 115 |
| Elvis Andrus | 50.5 | 76 |
| Mallex Smith | 50.3 | 96 |
| Trey Mancini | 50.1 | 113 |
There are some solid names here! Also, some not very solid names. Basically, GB% is not particularly predictive or indicative of much besides the idea that these players could potentially improve their output if they were able to hit the ball in the air more consistently. Hosmer made it a point of emphasis this offseason to get more lift on the ball and so far, he has succeeded.
A seismic jump, Hosmer is currently seventh in the league in average launch angle. He has not put a ball in play at less than 12 degrees. Not one. Last season, Hosmer only put 160 balls in play at a launch angle greater than 12 degrees, only 34.7% of his BIP! For context, Mike Trout, whose average launch angle was 22.2 degrees, hit 64.4% of his BIP greater than 12 degrees. It seems as though Hosmer may have completely reworked everything he does at the plate. Fellow staff member Michael Ajeto wrote a fantastic piece detailing some of those changes last week.
The question now begs, will this make him a more productive baseball player? More importantly, have we seen enough to feel confident in Hosmer’s apparent adjustment? Generally, launch angle is sticky, meaning it becomes consistent relatively quickly, even with smaller sample sizes. Eno Sarris wrote a great article prior to the 2019 season about how likely a large launch angle improvement would maintain. However, it was difficult to find a case as extreme as this, and in the midst of a 60-game sprint, fantasy owners will need to learn to either trust or distrust with a vastly different amount of available data than they are used to.
In response, we must seek out the “stickier” stats to tell us how one adjustment may or may not affect another. Namely, plate discipline, which stabilizes faster than batted-ball statistics because you will simply see more pitches per game than balls put in play. So, the sample size will grow to an appropriate size rather quickly. Having seen 45 pitches this season (still an imperfect sample), Hosmer has shown marked improvements in terms of plate discipline.
| Year | O-Swing% | Z-Contact% | SwSt% |
|---|---|---|---|
| 2018 | 33.1 | 85.7 | 12.1 |
| 2019 | 35.9 | 84.9 | 13.4 |
| 2020 | 19.2 | 92.9 | 6.7 |
Lifting the ball with a tremendous consequence would not instill much confidence, but Hosmer is doing so while simultaneously improving the rest of his game. It seems as if he has made a true improvement over the first week of this season and should be someone to monitor moving forward.
Photo by Elliot Baas/Rotoballer