On Tuesday I previewed arsenal scores, a metric created by Eno Sarris at RotoGraphs. The idea is simple: evaluate each pitcher’s pitches based on swinging strikes (good) and ground balls (also good). Sarris was kind enough to share his data with Inside the ‘Zona I’ve used it already to showcase D-backs starting pitchers. Now it’s time to highlight the bullpen and figure out just where everyone ranks out of 332 total relievers. So without further introduction (if you’d like more, read Tuesday’s work), let’s jump right in.


Randall Delgado, RHP

  • Rank: 50
  • Cumulative Arsenal Score: 4.89
  • Best Pitch: Changeup
  • Worst Pitch: Two-Seam Fastball

There’s a reason Delgado was thought of as a starter coming up –  his stuff was and remains quite good. While control has continued to elude him at times, he’s transitioned into one of the game’s better relievers. His changeup generates more whiffs than any other pitch he throws, getting hitters to swing and miss at 20% of them. When hitters make contact, over 52% of those changeups are hit on the ground. His two-seam fastball is another matter. Batters miss it infrequently (9% whiffs) and don’t exactly pound it into the ground (44% ground balls). He needs the fastball to set up the changeup, however, so he obviously can’t eliminate it. The two-seamer hasn’t work very well, so we’re mostly left with a middle of the road four-seamer and hopefully off speed pitches that continue to be effective.

Check out the changeup. It has strong fade and sink, making it a tough pitch to square up.

The two-seamer lacks much sink (especially up in the zone) and has some running action, but clearly not enough to get the best of Marcell Ozuna.


Daniel Hudson, RHP

  • Rank: 64
  • Cumulative Arsenal Score: 4.23
  • Best Pitch: Changeup
  • Worst Pitch: Four-Seam Fastball

Hudson has fully transitioned to the bullpen and the results have progressed nicely. His stuff is sharp and he hit triple digits on occasion with his heater. It’s no wonder that hitters were gearing up for the pitch – you have to start early if you want to catch up to that kind of gas. The changeup was the biggest beneficiary of the increased velocity as he got 18% swinging strikes on the pitch, and when it was put in play, it was hit on the ground 51% of the time. Even with major velocity, hitters only missed the four-seamer 11% of the time and usually hit it in the air. Hudson didn’t always show great command of the pitch, although it almost seemed to improve as he threw it harder. Maybe the extra velocity just allowed him to get away with a few more mistakes.

Hudson’s changeup is effective in large part because of his arm speed, but it has some nice sink and fade, too.

The four-seamer has some rise, but mistakes in the strike zone get hit.


Brad Ziegler, RHP

  • Rank: 120
  • Cumulative Arsenal Score: 2.22
  • Best Pitch: Changeup
  • Worst Pitch: Slurve?

Every metric has shortcomings and just like FIP and WAR don’t properly evaluate Brad Ziegler, neither do arsenal scores. Although ground balls are part of the evaluation, so are swinging strikes and that’s just not a big part of Ziegler’s game. Outliers are hard to evaluate for almost every system. Apparently Brad Ziegler’s changeup is hard to evaluate for hitters because they were hit on the ground 71% of the time. Batters missed them 18% of the time, too, making it one of the truly elite changeups in baseball. His breaking pitch is basically undefined, so we’ll call it a slurve. It isn’t nearly as impressive as it gets hit on the ground only 29% of the time while it gets only 11% whiffs. Ziegler uses it sparingly as his sinker and his changeup do the bulk of the work for him.

The changeup starts low and then basically just disappears.

Because of Ziegler’s arm angle, the slurve has unique movement and has clear two-plane action.


Andrew Chafin, LHP

  • Rank: 176
  • Cumulative Arsenal Score: 0.84
  • Best Pitch: Four-Seam Fastball
  • Worst Pitch: Two-Seam Fastball

Andrew Chafin was a revelation in 2015 and perhaps serves as an example of what can come of a fringy starting pitcher candidate when his stuff plays up out of the bullpen. A fierce competitor since his college days, Chafin was not one to back down. His four-seam fastball doesn’t get many whiffs, but generates a lot of ground balls for a four-seamer (53%). The two-seamer is a decent pitch for him, too, getting a ton of grounders (66%), but also hardly any swinging strikes. It’s no matter for the D-backs – they’ll take the ground balls and effective innings from the left side all day long despite the lack of swinging strikes that penalize him here.

His four-seamer has a little bit of arm-side run and he can spot it, making for a strong pitch.

Chafin’s two-seam offering lacks a ton of movement and is ineffective when not thrown at the bottom of the zone.


Tyler Clippard, RHP

  • Rank: 331
  • Cumulative Arsenal Score: -7.60
  • Best Pitch: Changeup
  • Worst Pitch: Fastball

The newest Diamondback is another victim of the methodology here. As Ryan profiled yesterday, Clippard has been very productive over the years, but he’s so opposite of Brad Ziegler that it’s bizarre. Clippard is an extreme fly ball pitcher, hence the exceedingly low arsenal score. The changeup gets 15% whiffs, but only generates ground balls 16% of the time the ball is put in play. The four-seamer gets swung at and missed 12% of the time and gets hit on the ground 19% of the time. None of that is particularly impressive, but it’s so extreme that he generates a ton of easy fly balls. Again, those on the extreme ends of the spectrum are hard for metrics to analyze and this is where we have to use our common sense and other information to identify an effective reliever.

Clippard’s changeup has some sink and is thrown with good arm action as it looks fastball out of the hand.

It’s easy to see why the fastball is so effective at generating fly balls as it has a ton of backspin and rise to it.


While Silvino Bracho, Josh Collmenter and others weren’t available for analysis here for a variety of reasons, there’s plenty to like in the D-backs’ bullpen. Even players with low scores are only low on the ladder given the methodology here, not because they’re ineffective pitchers. We’ll take Chafin and Ziegler’s ground balls all day and apparently everyone is cool with Clippard’s extreme fly ball ways (it works for Collmenter). Meanwhile, Delgado and Hudson really do have some strong stuff. Overall, it’s not a knock-out bullpen but it’s far stronger than most realize. Just because it’s unconventional in nature doesn’t mean it won’t be effective. In fact, it might just be effective in part because it is unconventional.

3 Responses to D-backs Relief Pitcher Arsenal Scores

  1. Anonymous says:

    Generally fly balls not hit at this rate means deception combined with being overpowering. You could probably graph the two together to see the emphasise, meaning which one is heavier velo or deception

  2. Anonymous says:

    Hit out, if hhav is low. Re clippard

  3. Dave-Phoenix says:

    I’ve never been a big fan of the arsenal data because there are quite a few pitchers like Ziegler and Clippard with high on the field results and low arsenal scores.

    Not all data is good data in my opinion.

    If the D-Backs lived and died by this data they probably would have had someone else be the closer last year, somebody who would not have had 30 saves with only 2 blown opportunities…..

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