Let’s talk about Aaron Nola’s changeup

When you think of Aaron Nola and his pitching repertoire, what do you think of? Are you a fan of the big looping curveball that makes good hitters look foolish?

Do you prefer the four-seam fastball, the one that rides on a batter to get him swinging?

Ah, no, I know what you’re thinking. You’re thinking of that nasty, two-seamer that rides back over the outside corner to get either a right-handed hitter looking or a left-handed hitter backing out of the way.

All good choices since these pitches are the ones that make Nola the ace that he is. However, they’re not what we’re going to talk about today.

No, we’re here to talk about the pitch that has seen the biggest uptick in usage over his years in the majors, the one that is beginning to become one of the most deadly in his arsenal: the changeup. Destiny Lugardo at Phillies Nation did a great writeup about the pitch and the levels he reached with it this past season, but what I want to do is track what the pitch has done since he came into the league. Is it acting differently than in the past that he trusts it more?

Coming out of college, Nola was highly regarded due to his ability level and because he felt so close to the majors already. Here is the scouting report from Baseball America before he got drafted.

[Nola’s] fastball sits 93-94 mph and touches 95 regularly, and he reached back for 96 in a hyped, head-to-head showdown with Vanderbilt and Tyler Beede in March. Nola’s fastball command ranks toward the top of the college class, as he can pitch to both sides of the plate, though his walk rate has increased (1.3 to 2.3 per nine) this season as he has thrown more sliders. His strikeout rate has jumped even more (8.7 to 10.7 per nine). Nola arrived at LSU with a plus changeup with sink that looked like his fastball out of his hand, but he has lost feel for his change while improving his slider, which was once below-average. Scouts give his slider average or better grades as he has added power to the pitch, but they would like to see a return of his plus change.

It’s funny how a pitcher can change once he reaches professional baseball. Nola rarely if ever throws a slider anymore, having adapted that pitch to professional hitters and creating the curveball that can freeze just about anyone. But the thing to take note of here is that the changeup he was throwing in college was almost vanished, having regressed due to desire to make the slider a better pitch. Fast forward a bit to his first rankings in BA and the concern for the changeup and how much it had gone backwards was still there.

He backs up the fastball with a slider and changeup, which each have the potential to be plus in the future. He’s on a fast track for sure, but the Phillies would like to see him improve in a few areas before they consider him for the rotation. Most notably, they’d like to make sure he stays consistent with his arm slot. When it drops lower than three-quarters, his slider tends to flatten. His changeup, a plus pitch earlier in his career, has regressed.

It was an issue for him as he moved through the minors and as he was promoted to the major leagues in 2015. But a funny thing has happened since he worked on his game at the major league level. All of a sudden, that pitch that he wasn’t so fond of, he’s been trending toward using it more and more.

Nola has actually made his changeup one of his go-to pitches in his arsenal. That 27.4% usage in 2020 made it the pitch he used the most by mere percentage points over his four-seam fastball. He trusts it and uses it as a weapon more often than not. So what happened? What changed with the pitch that he uses it so much now?

Let’s first look at what it does. If we want to talk movement, the horizontal and vertical break on the pitch hasn’t really changed much over time.

Not a whole heck of a lot going on here, which is not to be interpreted as a bad thing. If anything, we can see that he has adapted the pitch to not have so much vertical movement, thus staying in the zone a little bit longer and looking more enticing to the hitter and inducing swings more often than not. The evidence for this is pretty strong as the whiff percentage on the pitch has gone from 26.1% in 2015 to 36% in 2020. That is a pretty substantial jump in making people miss. You can really start to see how much the pitch is tightening up as far as movement too. Here is a video of Nola getting a swinging strike in 2020.

Here is the same pitch to a pretty dangerous left-handed batter in 2017.

And lastly from 2016.

It’s not a huge difference in the pitch, but there is a difference in how much it is diving away from hitters, probably mostly by design. So again, what’s changed with the change?

The answer might be as simple as feel.

We all are aware that the changeup is the pitch whose effectiveness is mostly determined by how the pitcher feels when throwing it. If he cannot get that “feel” for the pitch, he’ll either limit the amount of times a batter sees it or eliminate all together. Perhaps Nola just wasn’t able to find a grip he liked enough as he moved through college and and the minor leagues, thus robbing him of a third pitch. Under the tutelage of various major league coaches, there has to be someone who gave him the grip or touch he needed in order to get that “feel” back to where he would be comfortable throwing it whenever he needed that big out. That seemed to be the big focus of his spring training this past season, getting back to where he wanted to be in the previous years.

“It has felt really good,” Nola said. “It has felt like it should. I just want to fill up the strike zone and keep the ball down a lot this spring. That’s kind of the key. Get ahead of guys and stay ahead of guys. I just want to focus on having that tunnel vision around the plate. I had some starts where it all worked, but I felt like I used my curveball a lot more in the middle and late in the season. My changeup wasn’t as consistent as it was in previous years. I am just trying to get back to throwing it down for strikes more.”

Ah, tunneling. An elusive concept that still confuses the heck out of people, but can be broken down simply to mean you want each pitch to approach the plate in the same “tunnel” so that they all look the same to the batter. A number of years ago, Baseball Prospectus updated their data set and introduced some new ways to look at tunneling found in this article here. The more those pitches can all look the same, the bigger the advantage the pitcher has since the late movement of each will determine the outcome of the at bat. Judging from the available data that we have on tunneling, it looks like Nola may have actually gone backwards with his tunneling capability which is why he mentions it so specifically in the spring training article. The information can get a bit into the patented “gory math” part of baseball statistics, but trust me when I say that tunneling was an issue as 2019 was his worst season for tunneling. As of yet, they have not released any data from 2020, which is unfortunate because that is what we are after. Instead, we’ll have to rely on 2019 and assume that he was successful in his pursuit. Judging by the amount he threw it in 2020, he’s not just waiting for a “put away” situation; he is going to throw it whatever the count may be.

Without knowing what exactly Nola did differently, the answer might just be that simple: he’s found the feel of his good changeup and has improved upon it. He trusts a lot more than in the past and has used it, along with everything else he can throw, to vault himself into discussions as one of the top pitchers in the game.