The Royals have had a roller-coaster season. No team has seemed more alternately doomed and formidable while playing to a near .500 record. Because they came into the season poised for a playoff run, with the Shields/Myers trade looming large, the stakes for the team are high. Yet, depending on the day, the team appears to be either ready to make a deep playoff run on the back of fireballing phenom Yordano Ventura or poised on the precipice of failure and an impending teardown.

Much of the anxiety imparted by the Royals stems from the performance of the so-far anemic offense, which generated higher expectations in the spring. Seemingly skilled hitters like Billy Butler and Mike Moustakas have not met their relatively optimistic projections. Without an obvious explanation (such as injury) for their underperformance, hitting coach Pedro Grifol got the axe in late May, replaced by Dale Sveum, the former Cubs skipper.

Since Grifol’s ouster, the club’s offensive attack has improved upon its pre-Sveum average of 3.79 runs per game, scoring at a 4.96 RPG post-Sveum pace, which has led to a lot of praise for the new hitting coach. (The Royals have hit to the tune of a .753 OPS in June, more than 100 points (!) better than in May.) But before the resurgence, when Grifol’s firing seemed like a distraction from what was soon to be an ugly season, Sveum had some interesting things to say about the Royals’ offense. From ESPN:

'The bottom line is we've struggled with elevation and we've swung at pitches down in the zone probably way too much,' he said. 'From thigh high to the top of the strike zone, we're not doing enough damage.'

(Emphasis mine.)

Sveum’s quote stood out. He’s narrowing the struggles of the club down to literally one dimension: their command of the vertical aspect of the strike zone.

Contrast that with quotes from other hitting coaches, for example Dodgers coach Mark McGwire:

'I love seeing frustration in the opposing pitcher, and I saw that with Storen,' McGwire said. 'I love seeing our hitters work the count. When you work the count and see as many pitches as you can each at-bat, it sets the tone for the rest of the lineup, and it sets the tone for the game.'

“Working the count” seems like a hollow platitude to me (although note well that I am not a baseball player). McGwire certainly doesn’t compare “working the count” to whatever the Dodgers’ hitters were doing before (idling the count? Stagnating within the count?), or explain precisely how the hitters’ new-and-improved approach will differ.

As a rule, hitting coaches’ mantras are built to that standard, usually employing some bland words about “selective aggressiveness” or hitting your spots or plate discipline. Sveum’s insight was different. It suggested a specific problem—too much contact being made too low in the strike zone—and professed a simple solution: Swing at fewer pitches down in the strike zone. Moreover, unlike a lot of coach-speak, there was a genuine insight there, namely that pitch placement influences batted ball type.

The Diagnosis
Let’s examine whether Sveum was correct in his identification of the problem with the Royals’ offense. The Royals are certainly not a team built for groundballs. Much of their offense comes from a trio of lumbering sluggers who do not benefit from trying to beat out weak grounders. The heavy bats in the Royals lineup need to get the ball in the air to do their damage.

As it happens, the Royals do have a groundball problem as a team. Their groundball mark of 50.3 percent this year ranks 27th in the league. That rate is also up from last year’s mark of 48.6 percent, lending some credence to the notion that the Royals’ problems have stemmed, at least in part, from excessive worm-burning. Those groundballs have come primarily at the expense of flyballs, which are down slightly from last year’s mark (1.3 percentage points down, to be exact).

Of course, a groundball hit by Norichika Aoki isn’t the same as one hit by Billy Butler. Speaking of Butler, a 53.3 percent groundball rate (his 2014 level) might seem unsustainably poor for the trudging DH, but it’s actually down slightly from his 2013 mark (53.5 percent). Similarly, Eric Hosmer’s grounder rate is basically unchanged from last year (54 to 53.5), and Moustakas’ mark is up only marginally (0.6 percentage points). In fact, the major contributors to the Royals groundball issues are Lorenzo Cain, whose rate is up roughly five percentage points, and Aoki, whose newfound presence in the lineup drives a significant portion of the increase in groundballs, as he possesses a 68.4 percent rate.

Still, there are significant problems with batted ball classifications, and seemingly minor differences across years could be masking underlying issues that players such as Butler are having with poor-quality contact down in the zone. In last week’s column, I showed that contact quality (as measured by the pitcher’s proximity to the center of the zone) influenced BABIP and ISO, so maybe despite the relatively small differences in batted ball subtypes for the Royals, they’ve had deeper problems with contact quality that sap power and OBP. I examined this possibility with PITCHf/x data.

First I looked at the height (in inches) of all the pitches the Royals’ starters swung at in 2013. Then, I contrasted that to their year-to-date swing height in 2014.

The results confirm Dale Sveum’s diagnosis. Fully seven of the nine Royals hitters are swinging at pitches that are lower, on average, this year than last. The year-to-year differences are difficult to contextualize on their own, so I also sampled 100 random starters from last year and looked at their changes in swing height. Of this random sample of 100, Butler’s drop would have ranked sixth; Hosmer’s first; Cain’s fifth; and Salvador Perez’s seventh.

In other words, several of the Royals’ most potent bats simultaneously decided to start swinging at lower pitches between 2013 and 2014, for reasons I don’t understand. Presumably Grifol wasn’t telling the young Royals to slash balls into the dirt, and I would think that a tenet of any hitting coach would be to try to swing at pitches as close to the center of the zone as possible, so how this bizarre disorder developed in the Royals’ clubhouse is mysterious. Nevertheless, it appears that Sveum was on to something: The Royals really were swinging more at pitches down in the zone, with detrimental results.

The Cure
So Sveum was correct in his assessment of the Royals’ hitting woes, but has he done anything to rectify them? The popular opinion of hitting coaches among many smart people is that they’re figureheads whose job is to serve as scapegoats when the bats fall silent. A more in-depth analysis would be needed to refute that opinion, but since Sveum’s hiring, the Royals’ offense has undoubtedly ignited, propelling them close to the division lead. Small-sample caveats abound (and Sveum admits as much), although they are countered to some extent by the fact that we are examining team-level stats.

More to the point, I wondered whether Sveum had actually treated the disease he identified, namely the Royals’ low-swing habit. Since he took over, the Royals have struck fewer groundballs, but as we saw above, the problem wasn’t the groundball rates, per se; it was the troubling trend of the Royals’ hitters to swing at pitches low in the zone. I did the same analysis as above but partitioned the season into the pre- and post-Sveum eras.

Five out of nine of the Royals’ hitters have seen their swing heights increase. Interestingly, several of those five had among the more severe drop-offs in swing height between last year and this year, suggesting, perhaps, that they were singled out as being in particular need of improvement.

The overall change in swing height is positive since Sveum arrived, so on average the Royals’ batters are swinging at higher pitches. Still, the difference isn’t huge. What’s more, the number of swings is too small to make for any statistically significant results just yet.

I offer this story, then, not as positive proof but as an interesting trend, one worth keeping an eye on as the season develops. I’m still intrigued by Sveum’s diagnosis, which was not only accurate but insightful. Maybe his comments provided a small window into the more advanced metrics that coaches and teams care about.

Moreover, if it’s really the case that expert hitting coach Dale Sveum dropped into the team, surgically identified the problem, and enacted a comprehensive solution in the space of mere weeks, it would defy all conventional conceptions of the importance of hitting coaches. More likely, Sveum’s arrival coincided with a little positive regression to the mean from the Royals’ dormant bats, and the recent hot streak was therefore more coincidence than effect. Whichever side you choose to believe, an advantage of the lengthy baseball season is that the truth will emerge as the sample sizes grow and we can examine a larger number of swings. If only for the sake of surprise, I’m hoping that Sveum’s miracle cure works.