Daniel Coulombe, junkballer extraordinaire

What is a junkballer, exactly? Webster’s Dictionary defines “junkballer” as For me, two key characteristics come to mind: A junkballer should have fairly low fastball velocity, and they shouldn’t rely on that fastball too often. So someone like Bartolo Colon — who lives in the upper 80s in terms of both fastball velocity and usage — doesn’t qualify, nor does Andrew Miller and his high-octane, slider-heavy approach.

Of course, most junkballers have a third character, connoted though not denoted: They’re usually not very good. When you can’t overwhelm the hitter with a powerful fastball, you typically won’t stick in the majors, much less dominate. But that rule doesn’t always apply. This is where we meet Daniel Coulombe — the Athletics southpaw with a fascinating 2016 and an even more fascinating pitch mix.

Ignore his 4.53 ERA — that doesn’t do him justice. The 26-year-old rookie blew away opposing hitters, ranking in the 86th percentile* with a 28.0 percent strikeout rate; his 19.2 percent K-BB rate put him in the 84th percentile*. Plus, when his adversaries managed to put the ball in play, they usually didn’t elevate: Coulombe’s 62.2 percent ground ball rate finished just outside the top 10.

*These rankings, and all the rankings in this post unless otherwise noted, consist of the 382 pitchers with at least 40 innings in 2016.

Coulombe’s success in these peripheral metrics made him one of the better relievers in baseball. His 83 cFIP was better than 2016 All-Stars Alex Colome, Jeurys Familia, and Wade Davis. In a perfect world, where Coulombe strands more than 65.8 percent of his baserunners — and where fewer than six of his 25 fly balls didn’t leave the ballpark — he posts a sub-three ERA, as each of those pitchers did, and gets the attention he deserves. We don’t live in a perfect world, of course, but it’s fun to think about what could have been had the baseball gods let the metaphysical dice fall in a different pattern.

So what makes Coulombe tick? To put it lightly, he doesn’t operate like Colome, or Familia, or Davis — because he throws a lot fewer fastballs. Last season, he had the third-lowest clip of hard offerings:

Those two fellows ahead of Coulombe? As you may have heard, each of them leans heavily on the knuckleball. Among non-knuckleballers — i.e., normal human beings — Coulombe leads the way.

So what did Coulombe lean on the most last year? Per Brooks Baseball, he threw his slider 32.0 percent of the time. And it was a pretty nasty pitch — just ask Nelson Cruz:

GIF via MLB.com

While the slider traveled a little bit slower than average, its horizontal movement — or lack thereof — made it pretty distinct. Only five other relievers with at least 100 sliders had less run than Coulombe’s -0.8 inches. That arm-side break probably explained why the slider fooled righties (18.2 percent whiff rate) as well as lefties (28.2 percent whiff rate).

It also could be the reason why, rather than pairing the slider with an offspeed pitch, Coulombe decides to roll with another breaking ball — a curveball, deployed 29.6 percent of the time. It’s a pitch Kendrys Morales had some trouble keeping up with:

GIF via MLB.com

Where the slider’s vertical horizontal made it deadly, the vertical movement on the curve sets it apart. Four other relievers with 100 curveballs had more drop than Coulombe’s 9.5 inches. That bite was pretty indiscriminate, too — Coulombe blew the curve past lefties (16.0 percent whiff rate) and righties (16.7 percent).

Neither the slider nor the curve, it should be noted, were exceptional when compared to other breaking balls around the league. In terms of whiff rates, both were above-average, yet outside the top tier for relievers:

But what the breaking balls lacked in quality, they more than made up for in quantity. Most pitchers lean on their fastballs, and since breaking balls and off-speed pitches are more deceptive, that puts a dent in their whiff rate. By deviating from this formula, Coulombe rode his unusual repertoire to a 90th-percentile swinging-strike rate. (And that’s just in terms of swinging strikes — they each had 80th-percentile or better ground ball rates.) Relying more on breaking balls is also how Rich Hill morphed into a strikeout machine and an upper-echelon starter.

This isn’t to say Coulombe’s fastball is useless. While it was in the bottom 10 percent of qualified relievers in velocity, at 90.2 mph — and had a subpar whiff rate to match — it got a ton of ground balls (61.9 percent of balls in play). At 30.2 percent of all his pitches, though, the fastball clearly wasn’t the star of the show. That slider-curve one-two punch was what made Coulombe great.

Coulombe’s the oh-so-rare high-strikeout, high-ground ball reliever. He may not have Zach Britton’s velocity — or his unfathomably low air ball rate, in fairness — but Coulombe can still attack hitters. If his results start to line up with his peripherals, this lefty will give junkballers a good name again.

Ryan Romano is the co-managing editor for Beyond the Box Score. He also writes about the Orioles for Camden Depot, sometimes. Follow him on Twitter if you enjoy angry tweets about Maryland sports.