Patrick Corbin Has Made Three Significant Changes

Let’s be frank: I’m late to the chase (field). Patrick Corbin has taken baseball by storm. And by now, we’ve all heard that he’s throwing more sliders. Lots of them.

But when people talk about Corbin or analyze him, it often stops there. His slider is a fantastic pitch and he’s making batters look like fools out there with it. But it’s selling Corbin short to say that throwing more sliders is why he’s having this fantastic start to the season. Thus, the focus of this article. I’ve found three major changes that Corbin has made and I believe they’re all having a significant impact on his breakout this season.

Let’s start with the obvious one...

Corbin is throwing far more sliders than he did in the past

This is the one we all already know about. Not only have we seen it in our games but we’ve heard every MLB voice and their brother talking about it. And for good reason. Why not throw more of your best pitch?

This chart may surprise you, as it did me. I thought the gap between 2017 and 2018 would be bigger than it is (and it sort of is - see next section) but it’s honestly not a HUGE increase over last year. Keep in mind, Corbin is still throwing a TON of sliders - he has the 4th highest Slider% in baseball behind Tyson Ross, Chris Archer, and Clayton Kershaw. But it’s not like Corbin became a one-trick slider pony.

Corbin’s strikeout rate, however, has jumped considerably more than one would expect from a small increase in slider usage. He was at 21.6% K% and that is all the way up to 39.3% so far in 2018. While 39.3% is almost certainly unsustainable for a starting pitcher, what has caused this jump?

Well, a ~50% incresae in whiff percentage on your slider that you’re throwing more often will certainly explain most of that jump. But this change, on its own, is almost certainly not sustainable. But is it possible that a good portion of it is? Well, let’s take a look at the other two changes.

Corbin is now throwing a really slow slider-curveball-thingy

Again, this is something that’s not entirely new but it gets a lot less exposure. The word out on the street is that Corbin is simply adjusting how he throws his slider to throw it slower at times. Pitch F/X tracks it as a curveball, so they’re at least registeing as separate pitches.

What’s amazing is the degree of separation in the velocities and how it appears to be improving as he throws it more. First, here is a chart of the pitch usage:

It looks like Corbin has settled in around a ~40% slider percentage and ~12% slow slider-curveball-thingy (which I will now call a “slurveball” for the rest of this article). Combined, this is about 52% (which does make the 2017 to 2018 bump in slider usage bigger, as I noted from above).

But what’s really standing out to me on the slurveball is the velo difference between that and his slider... and how it’s gotten even lower his last two starts:

This chart shows both the average velocity as well as the range of velocities for each game started. In his Dodgers start, the range was 73.8 - 77.4 MPH across 16 slurveballs. But look at that second Giants start (the 1-hitter): 66.0 - 73.7. That’s an amazing range, especially for a pitch he allegedly throws the same as his slider.

The sluveball, on its own, isn’t a great pitch. It’s got a hearty 18% whiff%, but that’s about average for a curveball. And batters swing at it a lot less (55% vs 32%) than his slider. Where it really excels, however, is that only 1 out of the 50 slurveballs Corbin has thrown this season have been put in play. As I’m sure you’ve noticed from watching that game, he’s using the pitch to catch hitters offguard and buy a strike.

And you want to know why? Because out of the hand, it looks just like his slider:

That’s a pretty healthy release point on his pitches. While there is a slight difference between the pitches (the sliders and fastballs are almost on top of each other; the slurveball is slightly separated), they’re still close enough that batters are likely struggling to pick it up at the plate. This is further compounded when you look at the movement on the pitches:

FanGraphs

In terms of movement, the slider and slurveball are practically the same pitch. So while the slurveball, on its own, isn’t a special pitch, it’s making his slider that much more effective. This is one more thing that batters have to consider at the plate. It looks like a slider out of the hand, moves like a slider, just ~10 MPH slower.

Corbin has effectively added a third pitch. But what about his fastball? No ones talks about Corbin’s fastball...

Corbin has turned his fastball into a plus pitch thanks to improved command

THIS is the change I see no one talking about. Some background into how I saw this and why I think this is a bigger change than people realize:

We’re all aware that Patrick Corbin’s career has been very up-and-down. And the source of the struggles that Corbin has faced have almost exclusively been against right-handed hitters:

Sean Testerman

Look how closely Corbin’s overall ERA depends on his FIP against right-handed hitters. The slider has always been good for Corbin against right-handers, but his fastball has been getting demolished. From 2012 through 2017, Corbin’s fastball was the 20th-worst fastball among 138 starting pitchers with at least 500 IP thrown (-0.72 wFB/C). This year? He’s now 19th-best out of 95 qualified starting pitchers (+1.23 wFB/C). This is almost a 2 run swing (per 100 fastballs) in just one year. Now, this is a number that is quite “noisy” but there is some merit to this change for Corbin in the hopes that it might be sustainable.

I noticed something over his starts this season: Corbin seemed to be getting more whiffs on his fastball than I remember. Sure enough, the data backed this up:

Not only that, but hitters were also struggling to square up his fastball, even when they knew it was coming:

I figured that the improved slider and slurveball were having an effect, but I wondered if there was anything deeper. Last year, I noted that Corbin had found success from June through the end of the season by keeping pitches out of the strike zone. Well, how is his fastball doing this season?

This is a chart comparing his 2017 fastball location (left side) versus 2018 fastball location (right side). I cannot express this enough: THIS CHANGE IS MASSIVE.

Corbin used to throw pitches across the whole plate, especially on the inside to right-handed hitters. Where do right-handed hitters like the ball most of all? Middle-in. Now, in 2018, he’s almost exclusively throwing it on the outside part of the plate (to RHH). This is a significant improvement in command that we haven’t really seen from Corbin before. But this is a fundamental change that can pay off massive dividends to Corbin’s success against right-handed hitters (and this is in addition to the increased slider usage and the brand new slurveball).

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It is incredibly impressive how much has changed for Corbin in simply one season. But the more I look into it, the more that I can believe this breakout is here to stay.

However, we can’t expect Corbin to keep pitching this good, or at least we shouldn’t expect this level of success. If the season ended today, Patrick Corbin would end up with the highest K% of all-time. It is not reasonable to expect him to continue this pace after 5 starts and we should expect his K% to regress.

But that doesn’t mean that Corbin can’t keep pitching like an ace. His slider is truly elite, the slurveball is now a very-effective third pitch, and he’s keeping right-handed hitters off his fastball. Now the question is: how long can he sustain all three of these aspects and how will MLB hitters adjust?

The slider and slurveball, in my opinion, are pretty easy to rely on sustaining a relative level of success and improvement over last season. To me, it comes down, quite simply, to his fastball command: can Corbin keep up this vastly improved fastball command over a whole season while still succeeding with his slider and slurveball?

This is what I will be keeping my eye on as the season progresses. If all three of these things hold true, I would not be surprised to see Corbin in the Cy Young race at season’s end.