How Eric Hosmer can become even better

Eric Hosmer's story is well known. General Manager Dayton Moore's first round pick in 2008, Hosmer reached Kansas City in 2011, where he had a fantastic rookie season and looked to be the star everyone thought he could be. Unfortunately, Hosmer's career has been up and down. Hosmer turned in an extraordinarily poor 2012 before a bounceback 2013. Most saw 2012 as a simple sophomore slump, but, again, 2014 proved thoroughly mediocre.

Fortunately, Hosmer is having a breakout season this year by all accounts. Hosmer is hitting a beautiful .310/.373/.464, walking almost 9% of the time. This adds up to a 130 wRC+; in other words, Hosmer is hitting 30% above league average, which is a career best. He is almost certain to best his 2013 total in Wins Above Replacement with about a month to go.

Still, Hosmer has immense potential, and he isn't quite reaching it. His average and plate discipline are both very good, but his one deficiency this year has been something that you wouldn't really consider: power.

Yes, Hosmer hasn't displayed much power this year.

At first glance, that statement doesn't make sense, because he has done this

...and this

...and this

...and this

all of which are from this year. Most impressive about Hosmer's home runs are the length and location. All four of those are to different fields--left, right, left-center, and right-center. And, according to ESPN's Home Run Tracker, Hosmer's average home run length is 420 feet, or second-highest among all batters with at least 10 HR.

But numbers don't lie. The best single stat to determine power is ISO, or Isolated Power. It's a simple stat that just subtracts batting average from slugging percentage; players with a higher ISO hit for more power more often than those with a lower ISO. Here is the full list of Royals regulars or semi-regulars with an ISO higher than Hosmer:

• Paulo Orlando, .193
• Kendrys Morales, .183
• Lorenzo Cain, .179
• Ben Zobrist, .178
• Alex Gordon, .177
• Salvador Perez, .171
• Mike Moustakas, .170

Hosmer's ISO is a mere .154. Among qualified American Leaguers, that ranks 46th out of 76, which is closer to Erick Aybar and Alcides Escobar than Mark Teixeria and Chris Davis. Obviously, Hosmer can hit balls very, very far. So what on earth is going on?

First, let's take a look at the rate at which Hosmer hits balls hard. We can see this by looking at what Fangraphs calls 'Quality of Contact Stats.' They explain it here:

Soft%, Med%, and Hard% are based on data from Baseball Info Solutions (BIS) which attempt to capture how well each baseball was hit...Quality of contact doesn’t perfectly correlate with success on the field, but in general, hitting the ball hard or allowing weak contact is better than the alternative.

For the early years of quality of contact stats, the BIS video scouts had to make judgments, but since 2010, the video scouts recorded the amount of time the ball was in the air, the landing spot, and the type of batted ball (fly ball, ground ball, liner, etc) and the BIS algorithm determines if the ball was soft, medium, or hard hit.

A hard hit ball can be a grounder, line drive, or fly ball; these stats measure how hard the ball is hit regardless of type. Here is Hosmer's placement among all 76 qualified hitters as well as the nearest four players above and below him:

Name	Team	Soft%	Med%	Hard%	AVG	OBP	SLG	wRC+	BABIP
Kendrys Morales	Royals	14.4 %	51.9 %	33.7 %	0.292	0.356	0.476	128	0.321
Kyle Seager"]">Kyle Seager	Mariners"]">Mariners	12.1 %	54.5 %	33.5 %	0.270	0.329	0.455	118	0.282
Robinson Cano"]">Robinson Cano	Mariners	15.5 %	51.0 %	33.5 %	0.278	0.325	0.422	108	0.313
Albert Pujols"]">Albert Pujols	Angels"]">Angels	15.5 %	51.1 %	33.3 %	0.246	0.311	0.489	121	0.218
Eric Hosmer	Royals	18.6 %	48.2 %	33.2 %	0.310	0.373	0.464	130	0.354
Prince Fielder"]">Prince Fielder	Rangers"]">Rangers	15.8 %	51.2 %	33.0 %	0.312	0.380	0.467	126	0.325
Shin-Soo Choo	Rangers	14.4 %	53.0 %	32.6 %	0.253	0.349	0.432	112	0.312
Nick Castellanos"]">Nick Castellanos	Tigers"]">Tigers	12.0 %	55.4 %	32.6 %	0.249	0.304	0.420	96	0.307
Brian McCann	Yankees"]">Yankees	14.1 %	53.5 %	32.4 %	0.245	0.329	0.483	121	0.244

Hosmer is near the top, ranking 21st. As you can see, the hitters around Hosmer are all above average except for Nick Castellanos. Hosmer is the most productive out of all of them, but that's partially due to good luck and success at putting balls in play.

So we've established that Hosmer hits the ball hard and that he has the ability to hit to all fields. Why, then, is his power so low?

The answer is simple: Hosmer hits too many ground balls.

It is impossible to hit home runs with ground balls*. The only balls that have any chance of going for a home run are those that are hit in the air. Furthermore, while it is possible to hit a hard grounder into the corners for extra bases, most ground balls do not go for extra bases unless the defense is involved in an extreme shift or extreme stupidity.

*citation needed

Ground balls do indeed go for hits more often-especially fast runners, like Jarrod Dyson, can regularly gather infield hits or bunt for hits on grounders, and slower runners can still put balls through the holes in the defense for singles (see Billy Butler's entire career).

But unless you hit for a high average and get on base a ton through walks, AKA the Joe Mauer approach to offense, hitting for power is the easiest way to increase your total offensive output.

The following is a table of the top ten ground ball hitters out of the 76 American League qualified hitters.:

Name	Team	LD%	GB%	FB%	AVG	OBP	SLG	wRC+	BABIP
Jose Iglesias"]">Jose Iglesias	Tigers	21.0 %	55.9 %	23.2 %	0.300	0.347	0.370	98	0.330
Joe Mauer	Twins"]">Twins	23.0 %	55.4 %	21.5 %	0.267	0.334	0.376	92	0.313
Anthony Gose"]">Anthony Gose	Tigers	20.7 %	53.7 %	25.6 %	0.254	0.313	0.372	88	0.343
Xander Bogaerts	Red Sox"]">Red Sox	20.6 %	52.9 %	26.5 %	0.320	0.349	0.414	107	0.368
Erick Aybar	Angels	20.2 %	52.9 %	26.9 %	0.269	0.303	0.324	77	0.300
Billy Butler	Athletics"]">Athletics	16.7 %	52.6 %	30.7 %	0.249	0.321	0.378	96	0.285
Eric Hosmer	Royals	24.4 %	51.6 %	24.0 %	0.310	0.373	0.464	130	0.354
Austin Jackson"]">Austin Jackson	Mariners	23.3 %	51.1 %	25.6 %	0.272	0.312	0.387	97	0.348
Robinson Cano	Mariners	24.6 %	50.8 %	24.6 %	0.278	0.325	0.422	108	0.313
Shin-Soo Choo	Rangers	20.8 %	50.8 %	28.4 %	0.253	0.349	0.432	112	0.312

Yes, that is our very own Eric Hosmer hanging out at seventh place, hitting grounders 51.6% of the time. Notice how hitting lots of ground balls correlates negatively with overall offensive production--Hosmer is the only truly effective hitter out of this bunch. Hosmer hits a fly ball only 24% of the time, which means that he can only get a home run once out of every four balls he puts in play at the maximum.

From the other direction, we can see that fly balls are very helpful to overall offensive production:

Name	Team	AVG	OBP	SLG	wRC+	LD%	GB%	FB%	BABIP
Jose Bautista"]">Jose Bautista	Blue Jays"]">Blue Jays	0.249	0.369	0.533	145	14.5 %	37.1 %	48.4 %	0.233
Brian McCann	Yankees	0.245	0.329	0.483	121	17.4 %	34.8 %	47.7 %	0.244
Luis Valbuena"]">Luis Valbuena	Astros"]">Astros	0.209	0.295	0.413	95	19.5 %	34.0 %	46.5 %	0.217
Brian Dozier	Twins	0.242	0.312	0.474	113	23.4 %	32.4 %	44.1 %	0.266
Chris Davis	Orioles"]">Orioles	0.256	0.342	0.548	140	24.7 %	31.5 %	43.8 %	0.311
J.D. Martinez"]">J.D. Martinez	Tigers	0.285	0.347	0.553	144	21.8 %	34.5 %	43.8 %	0.339
Edwin Encarnacion"]">Edwin Encarnacion	Blue Jays	0.268	0.361	0.535	142	20.4 %	36.0 %	43.5 %	0.263
Mookie Betts	Red Sox	0.282	0.328	0.463	111	18.6 %	38.1 %	43.4 %	0.298
Carlos Beltran	Yankees	0.276	0.338	0.474	121	21.0 %	36.5 %	42.6 %	0.307
Asdrubal Cabrera"]">Asdrubal Cabrera	Rays"]">Rays	0.263	0.318	0.422	105	21.5 %	36.3 %	42.3 %	0.314

Rather than the likes of Aybar, Gose, Butler, and Jackson we see Bautista, Davis, Martinez, and Encarnacion.

And, to be complete, line drives are also very good as well:

Name	Team	AVG	OBP	SLG	wRC+	LD%	GB%	FB%	BABIP
Jason Kipnis"]">Jason Kipnis	Indians"]">Indians	0.311	0.385	0.458	134	28.1 %	45.2 %	26.8 %	0.365
Chase Headley	Yankees	0.274	0.340	0.396	104	27.0 %	43.3 %	29.7 %	0.331
Ian Kinsler"]">Ian Kinsler	Tigers	0.305	0.356	0.449	122	25.3 %	34.1 %	40.6 %	0.333
Brock Holt	Red Sox	0.282	0.353	0.384	102	25.2 %	50.3 %	24.5 %	0.353
Mike Trout"]">Mike Trout	Angels	0.298	0.397	0.581	170	24.8 %	37.5 %	37.7 %	0.343
Chris Davis	Orioles	0.256	0.342	0.548	140	24.7 %	31.5 %	43.8 %	0.311
Miguel Cabrera"]">Miguel Cabrera	Tigers	0.353	0.452	0.572	179	24.7 %	41.8 %	33.6 %	0.400
Robinson Cano	Mariners	0.278	0.325	0.422	108	24.6 %	50.8 %	24.6 %	0.313
Eric Hosmer	Royals	0.310	0.373	0.464	130	24.4 %	51.6 %	24.0 %	0.354

This table combined with the Quality of Contact table helps paint why Hosmer is a good hitter: he hits lots of line drives and he hits balls hard.

But this table also shows the true limit to Hosmer's approach. Hosmer is basically the equal to every hitter on the table except for Trout, Davis, and Cabrera. But all three hit significantly more fly balls and therefore get significantly more home runs.

Hosmer's breakout season has been fantastic, but his offensive value will plateau unless he converts more of his grounders into fly balls. Again, we know that he has the ability to hit home runs out of Kauffman Stadium routinely. Here's another example for kicks-Home Run Tracker has it at 452 feet, which is out in every part of every ballpark in the Majors:

Though it's easier said than done, Hosmer has the pure ability to be one of the best hitters in baseball. Whether or not he makes the adjustment to be so is anybody's guess.