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It’s early, but Kelvin Herrera looks good

This may end up being important.

MLB: Kansas City Royals at Detroit Tigers Rick Osentoski-USA TODAY Sports

It’s no secret that the 2018 Royals might not be good. Like most non-contending teams, the focus of winning games is lessened a bit, while the focus of the future is heightened (ignore Miguel Almonte... ugh). This brings up the possibility of the Royals trading away pieces come summer time. The Royals won’t have any major chips, but they’ll have some very serviceable players that contending teams would love to have at the right price, such as Kelvin Herrera, Mike Moustakas, Lucas Duda, or Jon Jay. Out of this aforementioned group, the only one that has a chance of bringing back a return of at least remote significance is Herrera. This makes his performance in the first half of this season one of the more important factors for this organization during the 2018 season.

Now I try to never get excited over small sample sizes, I really do. But I’d be lying if I told you Kelvin Herrera didn’t look good in his few appearances. Let’s take at where he stands among 243 major league relievers early (yes, I know, small sample sizes).

  • 62.5% K% - 8th
  • 62.5% K-BB% - 7th
  • -1.32 FIP - 4th
  • -0.67 xFIP - 5th
  • 24.1% SwStr% - 13th
  • 68.4% O-Swing% - 4th
  • 97.6 MPH FB velocity - 10th

Now I’m not using these stats to make any sort of predictions for Herrera’s season, I’m only using these to show he’s be one of the better relievers in baseball one week in. So my goal is this piece was to not exactly figure out what he’s doing differently thus far, but more looking for signs of him returning to his 2014-16 self. For example, his O-Swing% (percentage of pitches outside the zone swung on) is already at a point it only reached once in 2017.

The first step in this was figuring out what went wrong. The initial reaction is to check the fastball velocity, as a lot of times that correlates with a pitcher’s decline. But actually, Herrera remained surprisingly consistent with his velocity last year, showing no signs of injury or other concerns on that front.

After looking at the velocity and finding nothing significant, I wanted to take a peek at the movement he was getting on his pitches. I did find something fairly interesting, that being the horizontal movement on his slider (kinda important for that pitch specifically). Maybe there was some correlation, as that pitch has been a very important part of his success as a major league reliever.

Tying right in this was the usage of his offspeed stuff. Trending way downwards from his 2016 mark, in which he threw his secondary pitches 39.7% of the time, to a 2017 mark of 33.1%, including a drastic decline towards the later months of the season.

The decline in Herrera’s offspeed usage was odd and for the most part unexplainable (perhaps signaling injury?), but so far through a sample size of 29 pitches, he’s thrown eleven offspeed (38.0%).

I wanted to hit back up on the slider movement for a bit, as I mentioned above how I thought that was important. He’s thrown it minimally thus far in his three games, but when I saw this one on Monday, I’m reminded of pre-2017 Herrera. Coming out of the hand, it looks good for Dixon Machado. But it later fools him with the some late dropping action.

And while we’re at it, let’s look at this changeup with great fade he used to strikeout Niko Goodrum. Another pitch that was extremely important to his success in the past, it’ll be huge if he could get this pitch going in 2018.

So to summarize the importance of Kelvin Herrera’s performance level in 2018, imagine a Kelvin Herrera with a 4.25 ERA, 4.30 FIP, and 8.5 K/9 and picture what he gets at the deadline with a half season remaining on his contract. Now imagine a Herrera that puts up numbers closer to a 2.75 ERA, 2.47 FIP, and 10.8 K/9. Picture what a contending team that needs a closer would give for that. Neither are going to bring back a superstar, but the difference in returns would be fairly substantial.