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The Royals are replacing the changeup with more fastballs

Bring on the heater.

MLB: Chicago White Sox at Kansas City Royals Jay Biggerstaff-USA TODAY Sports

If you’ve been watching the Royals ten games in, you probably know the production on this team has not been a fun development to watch. The offense has been dreadful (their team 73 wRC+ ranks 27th in baseball), paired with a disappointing level of results from the bullpen (5.87 ERA ranks 28th in baseball, 5.62 FIP ranks 30th).

But what has been a nice surprise is the starting rotation, ranking seventh in ERA and tenth in FIP among all major league teams. Now I wouldn’t expect this production to hold up at all (they are probably a below-average rotation, if anything), whether that’s due to small sample size, unsustainable performances, or just the fact that their playing in extremely cold weather games by baseball standards.

The nice output by the starting rotation early in the season is actually a familiar occurrence. All you have to do is look back to last year when their starters put up the fourth highest ERA in baseball for the month of April. During that early success, much was made about the success they were having with a certain pitch, the changeup (if you remember early in the season, Jason Vargas, Nathan Karns, Ian Kennedy, and Danny Duffy were just going berserk with their’s). This brief instance was described well in a piece by Hunter Samuels over at BP Kansas City last April.

Jason Vargas, Danny Duffy, and Ian Kennedy have combined to allow six hits in 60 at-bats that end on a changeup. Vargas’ .107 average allowed is the highest in that trio. Add in Nathan Karns and his .154 average allowed on the pitch, and you can see how the rotation has rolled to that league-best ERA thus far. Because when a pitch is as effective as the changeup has been for Kansas City, it makes sense to throw quite a few of them.

They were throwing them at an insanely high rate too...

Royals pitchers have thrown 380 changeups through Wednesday’s action this season, which is a rate of roughly 18.6 percent. The next-highest rate belongs to the Indians, at 13.9 percent. Put another way, the difference between the Royals changeup rate and the second-highest changeup rate is as large as the difference between the second-highest changeup rate and the 19th-highest changeup rate (Astros, 9.2 percent).

After the season had concluded, there were only four more teams that threw changeups at a higher rate than the Royals. But that same pitching staff had the seventh highest ERA and baseball, which eventually led to a pitching coach change early in the offseason. Dave Eiland had gone to the Mets and the Royals made an internal promotion to fill the open spot on the coaching staff with Cal Eldred. And since this was his first run as a pitching coach, there was little to none information on his philosophies.

But there is a number early in the season that screams change. The Royals are throwing 10.6% more fastballs this year. This rate of increase is far and away leading baseball.

Note that this may seem premature with the small sample size, but these type of numbers usually stabilize quickly

Top 10 Team FB% Increases

Team FB% 2017 FB% 2018 FB% Diff.
Team FB% 2017 FB% 2018 FB% Diff.
Royals 55.1 65.7 10.6
Reds 55.2 61.5 6.3
Cubs 58.3 64.5 6.2
Angels 49.9 54.3 4.4
Pirates 62.8 66.9 4.1
Blue Jays 58.4 62.5 4.1
Giants 51.8 55 3.2
White Sox 55.4 58.5 3.1
Red Sox 57 59.8 2.8
Twins 59.1 61.9 2.8

The Royals threw the ninth fewest fastballs in baseball last year. So far this year, they’ve thrown the second most. And obviously with this, their changeup usage has faded.

Top 10 Team CH% Decreases

Team CH% 2017 CH% 2018 CH% Diff.
Team CH% 2017 CH% 2018 CH% Diff.
Royals 14.3 7.6 -6.7
Phillies 10.6 5.8 -4.8
Astros 9.9 5.5 -4.4
Athletics 12 8.3 -3.7
Pirates 11.8 8.8 -3
Dodgers 11 8.5 -2.5
Rays 15 12.5 -2.5
Diamondbacks 11.3 9.1 -2.2
Cubs 8.3 6.5 -1.8
Cardinals 9.9 8.3 -1.6

The first thing that came to my head was the loss of changeup master Jason Vargas strongly influenced these numbers. But it goes far past that. Let’s start with Danny Duffy.

More fastballs, less changeups! Let’s check out Ian Kennedy.

More fastballs, less changeups! Now let’s take a peek at Jason Hammel.

So the point has been made that they are throwing more fastballs. But have the results been even good? And my answer to that is yes, yes they have. It’s early, but the Royals pitching staff as a whole is posting the lowest wOBA against fastballs in the majors. This comes after allowing the second highest mark in 2017 and the seventh highest in 2016. It’s still real early, but the differential between 2017 and 2018 leads baseball and it isn’t even close.

Fastball wOBA Differentials

Team 2017 wOBA 2018 wOBA wOBA Diff.
Team 2017 wOBA 2018 wOBA wOBA Diff.
KC 0.365 0.264 -0.101
LAA 0.339 0.288 -0.051
NYM 0.357 0.315 -0.042
SF 0.347 0.305 -0.042
ARI 0.328 0.288 -0.04
CLE 0.343 0.303 -0.04
COL 0.361 0.323 -0.038
PHI 0.358 0.324 -0.034
ATL 0.357 0.324 -0.033
TOR 0.349 0.316 -0.033
MIN 0.358 0.326 -0.032
CIN 0.387 0.36 -0.027
DET 0.36 0.335 -0.025
SD 0.357 0.333 -0.024
SEA 0.343 0.322 -0.021
CHC 0.33 0.312 -0.018
HOU 0.354 0.338 -0.016
TEX 0.365 0.354 -0.011
OAK 0.358 0.348 -0.01
MIL 0.334 0.329 -0.005
BAL 0.354 0.358 0.004
STL 0.333 0.338 0.005
BOS 0.306 0.316 0.01
CWS 0.353 0.363 0.01
PIT 0.353 0.364 0.011
NYY 0.339 0.357 0.018
WSH 0.334 0.357 0.023
MIA 0.366 0.396 0.03
TB 0.332 0.375 0.043
LAD 0.307 0.357 0.05

So other than throwing fastballs at a higher rate, what has changed? The first thing that came to mind was location. Here’s what I found.

Source: Baseball Savant

Right above is two years (2016 left and 2017 right) of fastball location.

Source: Baseball Savant

Pictured right here is the Royals fastball location in 2018. Just with a glance, it seems they’re throwing them low and inside more often, which perhaps could explain the improved results early on.

Are these results sustainable with the fastball? No. But is there a chance after having several subpar years with the pitch that Cal Eldred has perhaps improved what had been a problem that existed when Dave Eiland was running the pitching staff? Definitely.