In 2014, Kelvin Herrera finished with a 1.41 ERA, a 7.6 SO/9, 3.3 BB/9 and held opposition batters to a slash line of .214/.295/.266. He faced 285 batters and surrendered just 13 extra base hits. All of them doubles.

I don’t need to tell you he was the primary “H” in the H-D-H bullpen that powered the Royals to the Wild Card and beyond. Herrera was just as good in the postseason, throwing an additional 15 innings (!) with 16 strikeouts and a 1.80 ERA. He had a bit of a blip relieving Yordano Ventura against the A’s, allowing an inherited runner to score and then coughing up three consecutive singles to surrender another run. He settled down the next inning and the rest is October lore. He was magnificent in two of the three Royals wins in the ALDS and in all four games of the ALCS, allowing just four base runners. Herrera stumbled a bit and battled his control in the World Series, but by this point he had thrown over 78 innings, most of them in high-leverage situations.

Herrera is an extreme ground ball pitcher. His four-seam fastball averages 98 mph and generates a ground ball 53 percent of the time. Pure filth. He compliments that with a two-seamer that clocks around 97 mph and results in a ground ball over 61 percent of the time when it’s put in play. That’s when hitters actually make contact. He generates a miss in 20 percent of the swings off his two-seamer, 28 percent of the time against his straight fastball. Seriously unfair.

How about this tasty nugget? Herrera finished 67 plate appearances in 2014 with his two-seam fastball. Exactly one of those were put in play for extra bases. A double. One lousy double. That’s all that opposing hitters could generate off that sinker. For the record, they hit .185 against the two-seamer and the lone double pushed their slugging percentage to .200.

Then what about his change-up?

Herrera’s change has an average velocity of around 87 mph, or 10 mph slower than his fastball. With similar arm action and release point, and a slight arm-side fade, this is the offering that keeps hitters off balance. Herrera generates a miss on over 37 percent of his swings against the change. He will throw his change 24 percent of the time against lefties and it’s his “go-to” pitch against them when he’s ahead in the count.

Last summer was the first time Herrera has thrown more two-seamers than change-ups. I think that can partially explain his decline in strikeout rate. The two-seamer was a challenge pitch: Here’s something you can hit, but go right ahead, because you’re going to keep this on the ground and I’m going to get an out (or two.)

From Brooks Baseball, here is Herrera’s pitch selection through his career.

HerreraSelection

That’s quite a change between his sinker and his change and it tells me he must have confidence in his two-seamer to get results. I realize strikeouts are fascist and ground balls are more democratic, but whatever works.

Herrera gives Yost some flexibility in the bullpen. While Wade Davis and Greg Holland were strict eight and ninth inning pitchers, respectively, Herrera had the ability to throw more than a single inning. While Davis was tasked with getting three outs just four times last summer, and Holland never did, Herrera got more than three outs in an outing 12 times.  That was the most on the team.

Yost also relied on Herrera more than any reliever to get his team out of trouble. Herrera inherited 43 runners in 2014, by far the most on the team. (Second was Aaron Crow, who inherited 28 runners.) Herrera allowed just nine of those runners to score. That’s a rate of 21 percent, well below league average of 28 percent.

Herrera was outstanding last year. He’s been outstanding his entire Royals career. Such is the life of a seventh inning set-up man that he flies relatively under the radar.

If there’s one thing about Herrera’s season that raised a red flag was his drop in strikeout rate. In 2014, he whiffed 7.6 batters per nine, way down from his 2013 strikeout rate of 11.4 SO/9. I looked for a possible cause in the decline, but there isn’t anything that points to his falling strikeout rate as continuing. His swing and miss rate fell by a couple of percentage points and his contact rate was around 75 percent. Eh. Opposition batters swung more frequently in the past, and with the decline in missing bats, I suppose that’s as good a reason as any. Thankfully his 99 mph four-seamer and 98 mph sinker have been rock steady. Last year, his change-up velocity jumped to 90 mph, up three mph from 2013. The decline in strikeouts is something to watch going forward, but I expect it will increase in 2015. PECOTA is projecting a whiff rate of 8.9 SO/9. I’ll buy that.

Herrera is eligible for arbitration for the first time. While his performance was dominant, the system favors closers (because saves) over guys who just get the job done. While there’s no doubt in my mind Herrera can close, he’s not going to make Greg Holland money. Although his presence on the roster could render Holland (or Davis) expendable, should the Royals decide to jettison some payroll or add a bat in exchange for a reliever. Herrera asked for $1.9 million and the Royals offered $1.15 million. With the midpoint at $1.525, I expect the Royals and H1 (get it?) to settle at that number, give or take $25,000.