The Kansas City Royals are gearing up for another playoff run. This year’s team, as well as last year’s team, are fueled by an absolutely dominant bullpen. Ian York looks at one of the key pieces of that bullpen, setup man Wade Davis.
This year, the Red Sox based their hopes on a powerful offense compensating for adequate starting pitching and a mediocre bullpen. The Kansas City Royals, in comparison, bet on an adequate offense and starting pitching, and a completely dominant bullpen. With the regular season winding down, the Royals’ bet is looking a lot better than the Sox.
The poster child for the Royals relief pitching is Wade Davis, who most often pitches in the 8th inning. Although he may not be quite as good this year as he was in 2014, he is without doubt ridiculously, absurdly good. His ERA+ (439) and WHIP (0.794) are even better than last years’ (396 and 0.847 respectively), though his FIP (2.07 vs 1.19 in 2014) suggests a little luck with that.
Davis throws three pitches almost exclusively (four-seam fastball, curve, and cutter), with a rare sinker mixed in; Brooks Baseball also identifies a very rare changeup, though that may be just a mistake pitch. Here are his individual games this year, along with their outcomes (the number of walks and hits per inning, and the number of earned runs per inning) and the pitch mix for each. (Here the cutter is “FC”, the four-seam fastball is “FF, curve is “CU’, change is “CH, and the sinker is shown as “FT”, a two-seam fastball.)
There are not many earned runs in there, and there’s no obvious link to his pitch usage. In general, Davis uses his fastball and cutter extensively, with the curve thrown often enough to keep batters honest.
Davis throws hard, with his fastball averaging 95.9-mph according to PITCHf/x readings and his cutter at 92-mph (or, according to Brooks Baseball, which is usually closer to the stadium values, 96.6- and 93.2-mph respectively). His fastball has relatively little horizontal movement, with lots of vertical movement. Davis throws with a lot of backspin so that the ball rises relative to the path it would follow in the absence of spin (that is, due to gravity alone). We can compare break length, break angle, and speed of his major pitch types, using PITCHf/x data. (Since PITCHf/x labels his curve a “knuckle curve”, it’s shown as “KC” in this chart.)
Look at the broad distribution of break angles on Davis’s fastball. By slightly changing the axis of spin on the pitch, he changes the amount of vertical and horizontal movement of the ball.
The angle on his fastball ranges from about 0 (no horizontal break) to one that breaks arm-side. His cutter breaks in the opposite direction; rarely more than 5 or 6 inches, but enough that it will end up a few inches away from where the batter would expect a fastball to be.
Here is the distribution of all Davis’s fastballs and cutters from 2015 to right-handed batters. (These charts are shown from the umpire’s viewpoint, so the batter would be standing to the left of each chart. The grey polygon represents that de facto strike zone that umpires have been calling since 2014.)
If those clusters look very similar in their trajectory, that’s sort of the point. The two pitch types look very similar, aside from a minor difference in speed, but because the cutter moves in the opposite direction from the fastball and doesn’t rise nearly as much, swings at the cutter tend to produce either complete misses, or weak contact. This is more obvious when looking at the pitch location for left-handed batters:
To LHB, Davis tends to place the fastball on the outside edge of the zone, while the cutter starts out looking nearly identical and then bores in to the inside of the zone. This is the pitch that Mariano used to break bats, and Davis’s is just about as good.
It’s easy to appreciate both the similarities and the differences of the two pitches by choosing individual pitches to compare. Here is a fastball that Davis threw to Eugenio Suarez in the 9th inning on Aug 19, compared to a cutter to Anthony Rizzo from the 9th inning on May 31 (both batters fouled off the pitches). These are very close to the average location and speed of the respective pitches. In these charts, the fastball is red and the cutter is blue; the solid lines show the path that each pitch would take if there was no spin and the ball was only acting under the influence of gravity.
Especially compare the “Top view”, which shows the horizontal movement of each pitch. Although neither pitch deviates much from a straight line, they do move a few inches each, and in opposite directions. The side view shows the amount of rise each pitch has compared to its gravity-only path; the fastball has several more inches of rise than the cutter. But the two pitches, even in this slow-motion animation, look very similar, and follow basically identical paths until about a tenth of second before they reach the plate — far less time than any human can react in. Batters can’t distinguish these pitches except by their speed, but a batter swinging for a fastball will miss the cutter and vice-versa. They may miss only by a couple of inches, but that’s all that Davis needs.
Ian York has written about Koji Uehara, an impressive start by Eduardo Rodriguez, Joe Kelly’s approach in certain counts, the effect of better bullpens on offensive strategy, Rick Porcello’s resurgence, Matt Barnes’s first start, and a look at the much improved Jackie Bradley Jr.