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Danny Duffy’s 2016 season came out of nowhere

His power arm got him here, but his slider and changeup are making him great

Kansas City Royals v Tampa Bay Rays Photo by Brian Blanco/Getty Images

The 2016 season was a pretty huge dud. The Royals suffered a major championship hangover and found that having virtually no major injuries during 2014 and 2015 was pretty neat.

If there was one legitimate bright spot, though, it was undoubtedly Danny Duffy. He set a career high in innings (179.2), strikeouts (188), and Wins Above Replacement (WAR), according to Fangraphs (2.8) His 9.30 strikeouts-per-nine innings was the highest by a Royals pitcher since Zack Greinke in 2009. Greinke was pretty good that season, if I recall correctly. Duffy’s season would have been even more impressive if he hadn’t put up a 5.50 ERA in September.

To an extent, we all knew he had this in him. He entered 2016 just a season removed from posting a 2.53 ERA over 149 innings. The way he found success was far more surprising.

In 2014, his fastball was graded by Fangraphs at 13.6 runs above average. In 2015, a step back season for Duffy, the pitch still graded out at a nice 6.9 runs above average. From 2011 until 2015, the highest grade Duffy received for a pitch other than his fastball was a 2.5 in 2014 for his curveball. In total, during that same time span, Duffy’s other pitches registered a cumulative -23.4 runs above average. Ouch.

That all changed in 2016, however, which makes his evolution so surprising. If you would have asked any reasonable Royals fan the recipe for Duffy’s success as a starting pitcher before 2016, the answer would have been his fastball. If his fastball is dominant and he’s throwing it for strikes, he’ll be good.

However, by Duffy’s standards, his fastball was average in 2016. Opposing hitters hit .234 against the pitch. If you include his “sinker” in that number, which is really his two-seam fastball, that number jumps to .286. And that number is legitimate, because he threw that sinker a career high 20% of the time in 2016, and his slider barely outpaced his sinker at 22%. When Duffy threw the ball really hard, hitters performed fairly well. That does not typically fall under the “recipe for success” category.

What made Duffy successful, however, was the dominance of his slider and, get this, his changeup. For context, of the three seasons before 2016 that Duffy threw at least 100 innings, his changeup graded at a -9.7, -3.5, and -5.0, respectively.

In 2016, his changeup was at 6.3 runs above average. That is absurd, given his track record. According to this metric, his changeup was actually his best pitch, with his slider (not his fastball) coming in second at 4.3.

If we take a closer look, Duffy combined to throw his changeup and slider 39% of the time in 2016, and opposing hitters batted an anemic .196 against the pitches. The power numbers aren’t any better, with opposing batters slugging just .315 against those two pitches.

So when I tell you that Danny Duffy’s 2016 came out of nowhere, I mean it.

In the five years that he has been in Kansas City, he had never given any indicator that his secondary pitches would be respectable. It was always fastball or bust.

In 2016, Danny Duffy not only showed that his off speed pitches are respectable, but effective. And at times, specifically in his terrific, near no-hit game in Tampa, his slider and changeup were downright filthy.

Two years ago, I would have laughed at that sentence. But now, Duffy is a legitimate power arm with not one, but two effective secondary pitches. That bodes well for 2017, especially when you consider that many of his percentages were harmed by an outlier September.

I know you can’t discount his struggles in September, but we also can’t ignore that he threw 30 more innings than he had ever thrown as a professional. Either way, if Duffy continues to throw his slider and changeup effectively, 2017 could prove to be super gnar, bro.