2015 MLB Almanac: Absolute Kelvin Herrera

Kelvin Herrera

Per wikipedia.org, “the kelvin (K) is a unit of measure for temperature based upon an absolute scale.” It continues by explaining that “the Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases…in other words, it is defined such that the triple point of water (temperature at which the three phases (gas, liquid, and solid) of a substance coexist in a thermodynamic equilibrium) is exactly 273.16 K.”

In baseball, the letter ‘K’ has a whole different meaning. The name Kelvin also has a completely different connotation as well. For the last two seasons, Kansas City Royals relief pitcher, Kelvin Herrera has sort of become a household name due to his heroics in the postseason. He’s sort of become a fan favorite among baseball fans.

top 25 RPs

So when I released my Top 25 Relief Pitchers’ Rankings of 2015, many people were up in arms, especially a few who were wondering where Herrera was on the list, including Alan from Illinois who provided the following exchange with me:

  • ALAN: Where is Kelvin Herrera on this list?
  • FELIPE: He did not perform better than any of the pitchers listed here.
  • ALAN: He is better than anybody else on your list.
  • FELIPE: Including Zach Britton and Aroldis Chapman?
  • ALAN: Maybe…


  1. Kelvin Herrera–Mostly uses a fastball (69.2 percent usage rate, 97.2 mph) and once in a while, will mix in a changeup and two-seamer.
  2. Aroldis Chapman–Utilizes his 99 mph fastball 75 percent of the time. And just for good measure, will throw a nasty slider 16.8 percent of the time because life is unfair.
  3. Zach Britton–Relies heavily on a two-seam fastball (89.8 percent, 95.8 mph) and throws a rare slider.


  1. Herrera–Has the least impressive rates of this group. Compared to Chapman and Britton, he throws the most pitches inside the strike zone (44.7 percent), resulting in a high Swing Rate and Contact Rate (the latter being at 75.6 percent). He also has the lowest Swing Strike Rate (SwStr%) of anybody on this list.
  2. Chapman–Compared to the other pitchers, Chapman does not induce a lot of swings, especially outside the strike zone (O-Swg%–Pitches Swung Outside the Strike Zone of 35.2 percent is the lowest among the trio). But the “hit-it-if-you-can” approach he can utilize thanks to his blazing fastball (remeber, it averages 99 mph, tops in the league in 2015. For the sake of comparison, his fastball is almost two miles per hour faster than rookie Arquimedes Caminero, established closers Craig Kimbrel and Trevor Rosenthal, and Herrera) is highly visible in these numbers. A miniscule Contact Rate (second lowest among qualified relievers last season) and extremely high SwStr% (highest among relievers in 2015) is the result. Yes, he is that unhittable.
  3. Britton–as mentioned, relies heavily on one pitch to get by. It somehow works for the Orioles’ closer. He had the fourth highest O-Swg% among relievers in 2015, which hitters found it difficult to put good contact on pitches outside the strike zone (O-Cnt% of 43.2 percent). Britton also managed to have a great SwStr% (16.4).


  • Herrera had the highest Line Drive Rate (LD%) of anyone in this group (22.6 percent, 28th overall among qualifying relievers).
  • Herrera induces a fair share of grounders, but not enough to be considered a consistent ground ball pitcher.
  • Herrera also had the highest Hard Hit Rate (24.7 percent) of anyone in this trio.
  • Chapman forces more fly balls than grounders, but is not really a fly ball pitcher. That being said, he forces a lot of pop ups (second highest among relievers) and keeps a lot of balls inside the ballpark, despite his home park being one of the most hitter-friendly ballparks in baseball.
  • Based on what we know of Chapman’s stuff and style, none of this should be a surprise.
  • Britton is able to utilize his two-seam fastball to induce a lot of ground balls.
  • Matter of fact, no one had a higher Ground Ball Rate (GB%–79.1 percent) than Britton last season.
  • Britton’s LD% of 11.4 percent was the second lowest among relief pitchers last season.
  • Britton also led the league in Soft Hit Rate (34.0 percent).
  • An excellent display of keeping hitters off-balanced and frustrating them without having to give up many hard hits–despite the fact that Britton is basically a one-pitch pitcher.


  • Kelvin Herrera had no saves in 2015.
  • He also had the highest ERA in this group of relievers (2.71).
  • As well as the lowest Strikeout Rate (K%–22.4 percent).
  • Chapman, not surprising, had the highest K% (41.7 percent) and lowest FIP (Field Independent Pitching) of anyone in this trio. Yes, he gave up his share of walks (11th highest Walk Rate (BB%) among relievers), but as we saw, based on his stuff, he was able to easily overcome those issues.
  • Chapman also had the fourth lowest ERA among relievers. He also threw in 33 saves.
  • Britton had a good K% of 31.2 percent, despite being a pitcher that can induce an enormous amount of ground balls.
  • Britton leads this group in saves (36).
  • Britton also had the lowest BB% among this trio (5.5 percent).
  • Of course, a guy who induces a lot of grounders should be able to post an impressive SIERA.

For a more detailed look on FIP and SIERA, please check out our previous evaluations on pitchers.


It’s kind of silly two compare the top two relief pitchers in baseball with a guy like Herrera who is, without a doubt, a very talented pitcher and has made major contributions over the last two seasons with the Kansas City Royals. He even has something that Chapman and Britton probably want–a championship ring.

But as the numbers will show, Herrera might have what it takes to make it among the top 25 of 2016, but there are plenty of reasons why he missed the cut of our current top 25 rankings.

photo credit: Keith Allison/Flickr CC2.0 

author avatar
Felipe Melecio
Felipe Melecio was the managing editor for the blog Pathological Hate. He believes that math is your friend and numbers can be fun, especially when it comes to baseball. Keep tabs on all his knee-jerk reactions on Twitter: !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+'://platform.twitter.com/widgets.js';fjs.parentNode.insertBefore(js,fjs);}}(document, 'script', 'twitter-wjs');