D-backs Starting Pitcher Arsenal Scores

Analytics allow you do some really fun things. You can slice and dice numbers to create new ways of evaluating players that, frankly, weren’t possible just five years ago. One such metric, and one that I’m a big fan of, is the arsenal score. Eno Sarris has been rolling these out over at RotoGraphs for a few seasons now (his 2015 work can be found here) and give us a sort of way to grade “stuff.” But rather than just grade movement or velocity, arsenal scores use actual effectiveness (through z-scores) in terms of generating swinging strikes and ground balls, two of the best outcomes for any pitch.  Sarris was kind enough to share his arsenal scores database with Inside the ‘Zona so that we can get a better feel for what D-backs pitchers were throwing in 2015. Below you’ll find all starting pitchers who qualified for the study (based on number of pitches thrown) ranked out of 256 starting pitchers. So let’s get into the nitty-gritty, shall we?

Rubby De La Rosa, RHP

• Rank: 26
• Cumulative Arsenal Score: 3.69
• Best Pitch: Slider
• Worst Pitch: Four-Seam Fastball

Now if you take a peak at the entire list of arsenal scores for starting pitchers throughout baseball, you’ll see a bunch of familiar names at the top. Clayton Kershaw, Carlos Carrasco, Jake Arrieta and the like. So it might come as a surprise that De La Rosa ranks in the top 10% given his 4.69 ERA and 4.81 FIP in 2015. But there’s no denying that Rubby has nasty stuff. His slider generates a lot of whiffs – 17% of his sliders were swung at and missed in 2015. Sliders put in play were hit on the ground 57% of the time, too. Batters hit only .227 against the pitch and rarely slugged the ball. The four-seamer has strong velocity (96 mph average) but hitters don’t miss it often (8% whiffs). This isn’t uncommon for fastballs, but his is far from elite. 41% of them were hit on the ground  but batters did far more damage on the fastball as compared to the slider. As we’ve discussed, improved fastball command could be the key to Rubby De La Rosa turning a major corner, because the stuff is very good.

Here’s De La Rosa’s slider. Notice the late movement and two-plane break.

And De La Rosa’s fastball. This starts out over the plate and stays there. No surprise, Rubby was behind in the count and paid the price.

Zack Greinke, RHP

• Rank: 37
• Cumulative Arsenal Score: 3.04
• Best Pitch: Slider
• Worst Pitch: Four-Seam Fastball

This is obviously a name we’d expect to see near the top. Greinke has thrown a lot of innings, but as he’s progressed he’s added pitches (an effective changeup) and refined his command, truly honing his craft. Even though he’s aged, his stuff is still very good across the board and an examination of his arsenal scores reveals that he truly has no weaknesses – it’s just a matter of highlighting the best of the best. Like De La Rosa above, Greinke generated a ton of swings and misses on his slider (over 22%). It was hit on the ground 53% of the time and batters hit just .170 against it. The four-seamer wasn’t bad and was in fact above average. Batters didn’t hit it much more than the slider (.202 against) and hitters missed it 10% of the time, although it only generated 32% ground balls. Greinke’s ability to make all of his pitches work is truly impressive.

Here’s Greinke’s slider. Notice that it’s more vertical than horizontal in nature, helping its effectiveness.

And the fastball. It’s not a big velocity pitch and doesn’t have a ton of movement. Greinke is able to spot it effectively, although he didn’t here.

Patrick Corbin, LHP

• Rank: 43
• Cumulative Arsenal Score: 2.36
• Best Pitch: Slider
• Worst Pitch: Four-Seam Fastball

Corbin is the third straight D-backs starter that possesses a strong slider. We’ve seen plenty of it in Arizona and it’s a wipeout pitch, no doubt. Of course, he needs the fastball to get to it and that’s where things can get dicey on occasion. The slider generates 24% whiffs – more than De La Rosa and Greinke – but doesn’t have elite ground ball effects (44%). Batters hit just .159 against the pitch in 2015 and rarely hit it hard. The four-seam fastball was hit at a .330 clip, however, and only generated 8% whiffs. It’s easy to see that batters try to pounce on the fastball early, because if they get behind, they know the slider is coming.

Observe the vertical break on the slider. This one looks like a fastball on the outer third of the plate, then dives.

The four-seam fastball doesn’t have much movement and stays true, especially when elevated.

Shelby Miller, RHP

• Rank: 51
• Cumulative Arsenal Score: 1.80
• Best Pitch: Sinker
• Worst Pitch: Curveball

Given the lack of cutters in baseball, they weren’t analyzed here. I throw that out here because Miller started using the pitch in 2015 and it was a key to his success. For now, we’ll just focus on his sinker and curveball. The sinker was also a full time addition in 2015 and it worked very well for Shelby. The pitch doesn’t get many whiffs (6%), but it does get a ton of ground balls (55%). His curveball is also not a swing-and-miss pitch (9%) but generates fewer ground balls (50%). Miller’s repertoire is not exactly overwhelming, but he has a lot of tools in the toolbox and showed an improved ability to mix his pitches in 2015 to find success.

The sinker does it’s thing when thrown low in the zone: sink, fade and get ground balls.

The curveball isn’t the hardest pitch to pick up and is somewhat slurvy with some horizontal break. While functional, it’s not his best pitch for a reason.

Robbie Ray, LHP

• Rank: 156
• Cumulative Arsenal Score: -2.70
• Best Pitch: Slider
• Worst Pitch: Changeup

We’ve written a ton about Robbie Ray since he joined the big league rotation last season. He’s always had a good fastball and a changeup, but the breaking ball has long eluded him. But over the course of 2015, he started to throw the pitch more and more and it started generate more and more whiffs (about 14% in May in June and over 20% in August and September) while generating 42% ground balls over the course of the season. The changeup has faired well in terms of batting average against (.189) but doesn’t generate swings and misses (5%). The ball gets hit in the air frequently, which doesn’t play well in the arsenal score, but can still be effective. If the slider can continue to improve, these are two offering that can compliment a two fastballs that he can command.

The slider has big time horizontal break and makes it tough to hit.

His changeup clearly comes out of the hand at a slower speed despite similar arm action to the fastball. It has both sink and fade.

Having four pitchers in the top 51 is an impressive collection for Arizona. Could we have analyzed Miller’s cutter, his score may have jumped up the list. Greinke can control all of his pitches. De La Rosa has the raw stuff to pitch very, very well can his command take a step forward. Corbin has proven that he can be effective, especially when ahead in the count. Ray’s score is low, but his effectiveness was unquestionable and if the slider can become better for him, he can take a big step forward. We’ve known this is a deep staff and the arsenal scores back that up.