Nate Eovaldi: No Fastball Is Too Big to Hide

For his career, Nathan Eovaldi has a below-average strikeout rate. He’s been a little bit worse than league average by ERA, and a little bit better than league average by FIP, but even average is a strange outcome for a guy with a top-ten fastball by velocity.

Take a look at how much of an outlier Eovaldi is in graphical form. That’s him highlighted, against all starters that have thrown at least 1000 fastballs since 2007.

He should at least have an average strikeout rate, it looks like by this graph.

Two things first come to mind when you see a graph like this: straight fastball or terrible secondary stuff. Let’s take them in order.

Let’s re-do the graph from above but focus on the fastball. Here’s fastball velocity graphed against fastball swinging strike rate. Eovaldi is still an outlier, but when we graph the fastballs like this, we can use the color to highlight the straight fastballs. After flipping lefty fastballs so that all horizontal movement is on the same scale, we have to split all fastballs into three bins. The straightest fastball is, after all, very different from the average fastball and probably gets some benefit from that fact.

Eovaldi is once again highlighted, but remove the highlight and you’ll see a trend: the straight fastballs are mostly under the line, showing fewer swinging strikes than you’d expect given their velocity.

We know that horizontal movement is correlated to ground ball rates, so it’s not too surprising to see some red fastballs below the line — those are secret sinkers, or four-seamers with a lot of horizontal movement and good ground-ball rates. And the green fastballs above the line? Those are secret cut fastballs, or fastballs that look like four-seamers but have slightly cutter-like horizontal movement. Those get more whiffs.

So Eovaldi’s fastball is straight, and that robs some of his effectiveness. How about the second part? Are his secondary offerings no good? This time, let’s convert his swinging strike rate byt pitch type into indexed stats, where anything above 100 is better than league average.

Yes. Eovaldi’s secondary stuff is not really good. Until this season, every single one of his pitches was worse than league average by whiffs.

So why are we writing about a pitcher that is less than the sum of his parts? Because something has changed… again. Take a look at his splitter movement over the course of this season:

His catcher confirms, Eovaldi changed something about the pitch. Below is the grip he used to have, which he showed me in Oakland, about five games before he changed the grip. “Right after the Miami game,” is when Eovaldi’s splitter took off, Brian McCann told George King of the Post. “Before that it was more like a forkball. Now there is amazing action on it.”

The old grip on Eovaldi’s splitter.

Connecting the dots, it looks like Eovaldi is now holding the pitch more in his finger tips, and the velocity has gone up (it’s more 89 than 85 now), the horizontal movement has gone up, and he hasn’t lost any drop. It’s a great pitch now that he’s ‘tweaked’ it.

The whiff rate on the pitch is unchanged. That might seem strange, but this is how we circle back around. The whiff rate is unchanged, but Eovaldi is now throwing his splitter nearly a third of the time, and that’s the most he’s ever thrown a non-fastball. The whiff rate is unchanged but he trusts the pitch and it has remained good even as he’s gone to it more.

The new movement on the splitter Eovaldi now trusts.

Take a look at Eovaldi’s pitch usage over the last three years. He’s slowly thrown that straight, underperforming fastball less and less.

Over the course of his career, Eovaldi has thrown the fastball two thirds of the time in zero-strike counts. Since he started throwing his splitter more, he’s thrown the fastball 43% of the time in those counts. In a way, he’s hiding his fastball. His 97+ mph fastball.

Since Eovaldi has changed his splitter movement and usage, he’s struck out 18% of the batters he’s faced, which is much closer to league average than usual for him, and about 12% better than his career average before this year. His ground ball rate has surged to 55%, or 25% better than his career average before this year. He’s a better pitcher now.

Sometimes people wonder why we write about pitchers like Nathan Eovaldi. It’s because velocity is a great place to start. In his last start, Eovaldi hit triple digits in the seventh inning. Sure, his fastball is straight, but even a straight fastball, at 102, in a spot where you might be expecting the 90 mph split-finger… that might look like this.

This 102 mph fastball came in a 1-2 count.

No fastball is too big to hide. And now Eovaldi looks like he has the splitter to help hide it.