The Nationals traded for Royals' pitcher Kelvin Herrera this evening.
Not only did the Nationals trade for Kelvin Herrera, but they did so without losing Juan Soto, Victor Robles, or Andrew Stevenson. The first two were never in any real danger of being traded for a relief pitcher who will be a free agent at year's end, but the Nats escaped only giving up their 10th and 11th ranked prospects:
On the surface, this deal looks exceptional for the Nationals. Herrera is another back-of-the-bullpen type that only further deepens the Nats' options in that department. Here are a handful of things you should know about the Nationals' newest pitcher:
1. Herrera's strikeout "issue" is complicated
Herrera, like many other closers over the last half-decade, has made his name in strikeouts. He topped out at a 30.4 percent strikeout rate in 2016, and has a 23.4 percent clip for his career. His K% this season sits at 23.2 percent, which is both higher than last season and lower than his career average.
People will look at his dramatic K/9 drop as a red flag, but "per/9" stats are flawed and not generally a worthwhile stat to build an argument around. A pitcher who gets knocked around for five runs in an inning -- but gets three strikeouts -- can have the same K/9 of a different (much more efficient) pitcher who strikes out the side in order.
2. Herrera has basically stopped walking batters
His career BB% sits at 7.1 percent. His highest clip is nine percent (2014, 2015) and his lowest was a shade over four percent (2016).
This season, he's walking batters at a two percent rate. In 27 games this season, he's walked two batters. Two!
3. The jury seems to still be out on how good of a year he's had so far
Analytics are frustrating. On one hand, they can serve wonderfully as tools to help peel back the curtains and tell a deeper story - or dispel lazy narratives. On the other hand, they can be contradictory, confusing, and at times downright misleading.
Take, for instance, Herrera's baseline pitching stats. His ERA sits at 1.05, while his FIP sits at 2.62. On their own, both numbers are impressive. On their own, both numbers are All-Star level stats.
When you stack them against each other, however, the picture turns negative. While ERA is the more common stat, it's widely accepted that FIP more accurately represents a pitcher's true value (ERA's calculation makes the same per/9 mistakes that were mentioned above).
More often than not, when a pitcher's ERA is lower than his FIP, that indicates said pitcher has benefited from luck.
Throw in a 3.51 xFIP (which is the same as FIP, but park-adjusted) and we suddenly have a real mess on our hands. Is he the pitcher with the great ERA, the pitcher with the Very Good FIP, or the pitcher with the medicore xFIP?
4. He was a fastball pitcher, and then he wasn't, and now he is again
Take a look at Herrera's pitch usage over his career in Kansas City:
In only three years, he's gone from throwing a sinker 31 percent of the time to completely giving up on the pitch. That's pretty wild.
Since 2014, he's gone to the slider more and more in every year.
His current fastball usage would be the highest of his career. He only appeared in two games during the 2011 season, so those numbers aren't reliable. Going away from the sinker probably helps explain why his Ground Ball rate has dropped 10 percentage points, too.
5. The Nats finally have the bullpen they've been dreaming about for years
Doolittle, Herrera, Kintzler, and Madson is about as deep and talented as any bullpen in baseball.
Justin Miller, Sammy Solis, and Wander Suero all have flashed serious potential at points throughout the year. Austin Voth is waiting for roster expansion in September.
The Nats have been trying to build this type of bullpen for the better part of the last decade. Health obviously remains an important factor, but Rizzo's got the deepest pen of his time in D.C.
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