Danny Duffy’s Future Should Be in the Rotation


Mandatory Credit: Rick Osentoski-USA TODAY Sports

On Wednesday, Royals manager Ned Yost made some comments that seemed to indicate Danny Duffy would not only be competing for the final bullpen spot, but that he might be considered the favorite to win the job.  This is in contrast to what Jeffrey Flanagan was reporting in this article from Tuesday, in which he suggests the team preferred to send Duffy to Omaha, while giving the final reliever spot to Donnie Joseph. I’ve mentioned here that Duffy should head to Omaha as a starter, instead of being relegated to a bullpen role, but once again, it appears the Royals care not for what I have to say. Now, I don’t want it to be misconstrued: I think Duffy can be a good reliever. He’s got electric stuff, and it could play up even more out of the ‘pen. As a reliever for the 2014 Royals, Duffy could perform well enough to provide some value. It’s just that I think he could provide more value out of the rotation, and in my opinion, keeping him as a starter in the minors will do a better job of preparing him for making an impact than if he were to start the year in the bullpen.

This isn’t a discussion of the relative merits of the Royals’ decision, however. This is a discussion of Duffy, and what his future could be. In his career, Duffy has an 87 ERA+, 7.8 K/9, and 4.7 BB/9. While the strikeout rate is solid, the other numbers probably don’t inspire a ton of confidence, so it’s understandable if some people think Duffy’s best role is in the bullpen. That being said, those numbers were accrued over parts of three seasons, and in just 157.1 innings total. The overall sample is small, so it’s tough to analyze any one season without Duffy’s rate stats getting kind of crazy, but his overall line is mostly being driven by his poor 2011 season. That year, he threw 105.1 innings, struck out 7.4 batters per 9 innings, walked 4.4 batters per 9 innings, and had an ERA+ of 73.

Let’s examine that 2011 season more in-depth. Duffy is a fly ball pitcher, which can be a strong quality for a pitcher who calls Kauffman Stadium home. In 2011, Duffy allowed 135 fly balls. On those 135 fly balls, opposing hitters had a BABIP of .220. That may seem low, but the league average BABIP on fly balls in 2011 was .137, so already it looks like Duffy may have been the recipient of some bad luck. BABIP doesn’t account for home runs, so let’s take a look at some more numbers against Duffy on fly balls. In that season, opposing batters had a 1.056 OPS on fly balls, including extra base hits in 23.7% of their plate appearances facing Duffy. The rest of the league’s pitchers allowed a .790 OPS on fly balls, including extra base hits in 16.5% of plate appearances against. Granted, not all fly balls are created equal, so it is possible the fly balls Duffy allowed were hit with more authority. Still, that is a significant difference that seems way out of line with what Duffy’s stuff should produce.

Unfortunately, we don’t have the necessary data for the 2011 season to figure out the hang times on Duffy’s fly balls allowed, so we don’t have a perfect method for determining how many hard hit flies Duffy allowed. We do know he allowed a line drive rate of 19% in 2011, which wouldn’t suggest he was constantly giving up hard hits, though the data is incomplete so we can’t say for sure. I’ll get to another possible explanation in a bit, but I do believe it’s fair to suggest Duffy had some tough luck on batted balls in 2011. Even if he did allow more hard hit flies, a BABIP allowed on fly balls that is nearly 80 points above league average isn’t something you expect to see from a pitcher of Duffy’s caliber. For comparison, Duffy allowed a BABIP on fly balls of .094 in 2012 and .037 in 2013. Both of those come from the tiniest of sample sizes, but then again, 105 innings isn’t exactly a sufficient sample, either.

In addition to what may have been some bad luck, the 2011 outfield had Melky Cabrera in center field and Jeff Francoeur in right field, two players who lack even average range on defense. While they did make up for some of those shortcomings with their arms, Duffy wasn’t pitching in front of the elite outfield defense the Royals have in 2014. Lorenzo Cain and Norichika Aoki can both cover more ground than either Cabrera or Francoeur, and we all know what Alex Gordon is capable of. It’s certainly reasonable to think Duffy could have better results with the current version of the outfield than he had 3 years ago.

As I mentioned, there is one other explanation for Duffy allowing so many extra base hits on fly balls, and that is related to his pitch location. Here is a heat map of where Duffy pitched most frequently in 2011:

You’ll notice there is no part of the zone with a higher percentage of pitches than the heart of the plate. I’m not a pitching coach, but I believe most pitchers try and not throw strikes right down the middle of the plate, because major league hitters will hit those balls. Hard. If Duffy threw so many pitches in the middle of the zone, one could assume the batted balls would be more well-struck. Command and control have been issues for Duffy throughout his big league career, and it appears they may have been the biggest driver behind his poor 2011 season. I don’t think that is the sole reason for his higher BABIP allowed on fly balls, but it may account for some of it. In the last two partial seasons, Duffy’s done a better job of keeping the ball out of the heart of the plate, which is good. Duffy’s also done a worse job of keeping the ball in the strike zone, period, which is bad.

The question now becomes: Is there any hope for Duffy to improve his control?

In his minor league career, Duffy has walked 3 batters per 9 innings, but prior to his injury, he didn’t have a full season in the minors with a BB/9 above 3 since 2007, when he was 18 years old. With the exception of a 14 inning stint with High-A Wilmington in 2010, Duffy kept his walk rates in check throughout his minor league career.

Why, then, did he suddenly become a walk machine when he made the show? Unfortunately, we don’t have enough data to create a strong comparison to come up with a verifiable explanation, but I do have a theory. We all know Duffy is an emotional guy. He gets fired up before games, and he generally wears his heart on his sleeve. As a 22 year old, he made his major league debut. I think it’s certainly possible he wanted to make the best entrance possible, and he may have gotten so worked up that he started to overthrow. As I said before, I’m no pitching expert, and I haven’t broken down film on Duffy’s mechanics, but I do know that his velocity jumped quite a bit from 2010 (92.5 MPH) to 2011 (94 MPH). Knowing Duffy’s personality on the mound, I would suggest he was simply trying too hard to throw everything as hard as he could, and it may have affected his mechanics. His vertical release point dropped quite a bit throughout that season, which may lend some credence to my theory, as well. In addition to causing problems with his control, this change in release point could have also played a role in forcing Duffy to require Tommy John surgery. Since that surgery, his vertical release point has been slightly more consistent, but his horizontal release point has been somewhat volatile, and it seems he still hasn’t been able to reclaim the command he once possessed.

All of that was a very long-winded way of me saying I still believe Danny Duffy can be a valuable part of the Royals’ rotation. I’d hate for this bullpen experiment to turn into a long-term plan, because even if he’s never an ace, he has enough stuff to provide more value as a starter than as a reliever. It isn’t a guarantee, of course, but I do think that, given a larger sample size, his batted ball luck will even out, and having an outstanding defense behind him surely wouldn’t hurt. The biggest thing that appears to be holding Duffy back is his command, and that’s something he did well with in the minors, so hopefully Dave Eiland and the rest of the staff can get his mechanics under control, and get him to where he can consistently repeat his delivery. All of the things Duffy has struggled with in his short big league career are correctable, so now it’s just a matter of him having the opportunity to correct them. With his stuff, it’s simply too soon to give up on Duffy as a starter. If and when Bruce Chen is removed from the rotation, Duffy needs to be the man the Royals call upon, because he needs to be in the rotation unless and until he proves he cannot do it.