This is going to be a rabbit hole post. This sort of resembles my thought process when I go about looking at things and trying to come up with article ideas for you all. Be warned of this; the following may not be entirely sensical. The rabbit hole wasn't sensical either.
First, I stared at the Royals Fangraphs page for awhile. I've stared at it enough waiting for real baseball such that I've internalized some of the numbers. A big waste of time, really. Then I thought, "I'll go look at Eric Hosmer's page. He signed a contract recently, and the Mad Hatter is his agent. I'll look at his stuff for the 13.875th time."
Remembering some notable things about Hosmer's page, I went over to the batted ball section to look at his stupid ground ball rate again. It was 51.2% in 2014, and it's on a downward trend. That's nice that it's going down, but putting the ball on the ground that much is stupid unless you're named Jarrod Dyson or Lorenzo Cain or Terrance Gore or Alcides Escobar. That's a long list of names, but Hosmer's name is not invited to the grounder tea party. He's there anyway. Dumb.
Since his grounder rate is so high, I wanted to look at how pitchers approach him and how he swings at pitches. I looked at Brooks Baseball's zone page, which shows the pitch percentage and swing percentage within 25 discrete boxes representing the strike zone and outside the strike zone. Hosmer is often thrown pitches low and away, but so is basically everyone. So I wanted to look at how Hosmer compared to league average, which led me back to FanGraphs. FanGraphs has league averages for what I wanted to see.
After comparing the same pitch frequency and swing rate data between the two websites, I grew frustrated because they're not the same numbers. FanGraphs and Brooks Baseball must have different definitions of the 5x5 grid that comprises the strike zone and the encompassing area. Was it time to throw my hands up? Nope. It was time to go to a third website, Baseball Savant, that allows users to query the PitchF/X database directly. Hooray.
I decided to look at just the low pitches. I created a query that returned the percentage of pitches within the lower zone definitions as defined by me. I also restricted the query only to pitches swung at. No called/taken pitches in this dataset. Zones 7,8,9,13,14 (this is from the catcher's perspective) are the ones I included. First basemen only.
So I now had this dataset of players and all the pitches that were located down at which they swung. It had over 20,000 rows. Baseball Savant, however, includes some nifty graphs and visualizations that can do some aggregation for you. I clicked on all of them for a few players. Finally, I found something remotely interesting.
The average foul percentage in this dataset was something like 32.2% after I restricted the dataset to those players who had at least 100 swings. Eric Hosmer's foul rate was 38.7% and ranked 4th out of 52 players. Apparently, last year, Hosmer fouled off more low pitches than league average (among pitches swung at). I noticed a name right next to Hosmer's in the foul rate rankings: Freddie Freeman. Freeman's foul rate was 38.9%. I now have a very loose basis on which to compare the two young "cornerstones" (career numbers following).
Uuuuuggggghhhhhhh. Freeman is better in basically every way. Hosmer strikes out less and is a better baserunner, but that doesn't make up for a .038 gap in the old on base percentage and a .047 gap in slugging percentage. Freeman has been way better than Hosmer since entrance into the league. Their total PA is really not that far apart, either, so sample size concerns shouldn't be concerns.
So, back to what actually started the Hosmer rabbit hole, more or less. Grounder rate. Look at the massive differences in batted ball distribution between these two players. Freeman also plays his home games in a pitcher-friendly park, but he still puts the ball in the air A LOT. Freeman may not make as much contact, but he does a lot more damage with what contact he makes.
The differences continue to be stark. Hosmer actually swings less overall than Freeman, yet Freeman swings in the zone way more than Hosmer does.
There seems to be a fundamental difference here. My thought is that Hosmer keeps a level swing and that Freeman has some uppercut. However, pitches don't stay level on their way to the plate. Most of them sink. Here's Freeman doing wonderful things with a low and outside pitch. Here's Hosmer doing a more wonderful thing with a low and outside pitch in the same zone. What's different? Notice the count. 2-0 to Hosmer vs. 1-2 to Freeman. It looks like Hosmer just decided to take a big whack at a pitch, while Freeman decided to shorten his swing and ended up punching it somewhere. I was lucky enough that I made my snap judgment about Freeman's swing before I saw the count, so I'm hoping I didn't introduce any bias to what I expect each player's swing to be based on the count.
End of the rabbit hole. I guess I learned that Hosmer swings and makes contact, whether foul or not, with a bunch of pitches he shouldn't swing at in the first place. Freeman swings more but swings at better pitches. Thus, a huge gap in offensive production. I have a hypothesis regarding their mechanics that would take a scout's eye and lots of video time to test. I also wonder if the two players have different approaches based on the count. That seems to be it. Time well spent?