As Justin Steele pitched his way into the Cy Young conversation for the Chicago Cubs in 2023, he found a new level of success by consistently going with what worked best: A mix of pitches mostly consisting of four-seam fastballs and sliders.

In fact, his four-seam/slider mix worked so well that he basically only went with these two offerings — they made up a combined 96.5 percent of his total pitches.

But even with his success, Steele noticed that teams, especially those in the division, were starting to adjust to his two-pitch mix. He realized he couldn’t just continue with that combination and expect the positive results to continue. He needed to evolve as a pitcher and keep opposing hitters honest.

“Guys in our division — the Cardinals, the Brewers, the Pirates, the Reds, all them guys — I’ve faced them so much, you kind of have to show them new things, or they’ll be able to just eliminate pitches,” Steele told CHGO. “Everyone knows last year, I threw like 95 percent four-seams and sliders. [Hitters] can go up there and have it in your mind, like, ‘The ball is going to be moving this way, I can lean over the plate,’ different things like that.”

Knowing he needs to show more than just a mostly four-seam/slider mix, Steele has begun to more frequently throw pitches he’s had in his repertoire since he debuted in 2021.

Why Steele originally moved to a two-pitch mix

During his rookie season, he threw sinkers on 20.4 percent of his total pitches, including on 23.3 percent in September alone. But by about the end of June 2022, he was leaning much more heavily on four-seamers (FF in the figure below) and sliders (SL). In turn, there was far less usage in his other pitches, including the sinker (SI) and changeup (CH), a trend that continued into 2023.

Why did he make the choice to go mainly with a two-pitch mix?

“When I got here, I think I was trying to figure out, like, what’s going to help me help this team and keep me here? I kind of obviously figured out that the four-seam and the slider was what’s going to play at this level — and obviously, I mean, you throw enough sinkers and they get hit hard, you stop throwing them,” Steele said with a laugh. “That’s kind of what it was and just kind of realized, like, ‘OK, these two pitches are playing really well,’ and then I obviously took off with them two.”

From Cubs pitching coach Tommy Hottovy‘s perspective, a focus on simplifying things was important, too.

“We knew the stuff was electric, but just wanting to find a way to get him in the strike zone,” he told CHGO. “So, we talked through that pretty simply about, like, ‘OK, what are his two best pitches that we can kind of build our foundation upon?’ And then, mechanically, the things that we wanted him to kind of hone in, the little things and keep him consistent and give him a simpler approach. That way he’d kind of lock in the mechanical stuff we wanted to focus on.

“We knew those pitches were in the back pocket, but that’s kind of the direction we went because we wanted to just simplify some things with him, focus on his two best pitches, and then try to get on a nice run.”

Steele found success with the two pitch-mix in part because his four-seamer developed a unique “cut-ride” profile. That gave his fastball an unfamiliar shape, cutting into the hands of right-handed batters with more carry than a conventional cutter. By the summer of 2022, it had morphed from a league-average pitch into a highly effective “cut-ride” weapon (see figure below).

Steele’s cut-ride fastball grew into a pitch worthy of Cy Young consideration — by the end of 2023, his fastball became one of the most valuable pitches in baseball, ranking in the 95th percentile for run value (per Baseball Savant).

Why is this cut-ride fastball so effective? Well, imagine you’re a right-handed batter with Steele on the mound. Here’s what his cut-ride fastball looks like (in red) compared to his older fastball (in black). Notice how the red pitch appears to cut into the hands of righties, whereas the black pitch does not.

It’s important to note that his cut-ride fastball comes naturally because of his “supinator” mechanic, where his palm rotates toward the sky. This contrasts with the mechanics needed to throw sinkers and changeups. So, it’s understandable why they were limited in his mix for a while.

This season, though, he has begun to incorporate them back into his arsenal, with tweaks that leverage his supinator mechanics.

How Steele worked to re-expand his repertoire

Heading into his start Thursday, he’d thrown sinkers and changeups on 5.5 percent and 3 percent of his pitches, respectively. It’s a modest yet meaningful uptick in his pitch mix.

Steele told CHGO back in spring training he had done a lot of work on those pitches during the offseason, because being able to throw them with confidence in-game “would just open some more doors for me, have more doors for success.”

His work on changeups, for example, resulted in a different pitch grip that makes the most of his natural mechanics. Hottovy said that Steele previously was trying to throw the changeup “the way everybody was taught to throw it growing up, like pronate through the inside of it. The problem was, that’s just not how Justin throws.”

Over the last year or so, the pitching staff worked through different grip iterations to find something that worked with how he throws the baseball. Cubs assistant pitching coach Daniel Moskos was instrumental in making the change.

“Moskos was really good with Justin on trying to find a grip that he can almost throw like a cut-change and use seam orientation and make it fade and run away from a righty, so he didn’t have to try to manipulate it too much,” Hottovy said. “We worked on that a bunch last year, and he started getting more consistent and more confident with it. It just never really got to a point where he trusted it a ton in-game, but it’s always a pitch he’s had kind of in that back pocket that he’s been working on.”

The process was similar with the sinker — Hottovy said the two pitches now are “completely different versions of what he threw back then” — and the results have shown what they were hoping to see.

“Those two pitches, for sure, are going to continue to grow in usage as we move on,” Hottovy said.

Since they began working on changeups and sinkers in 2023, Steele has been able to generate the fade and run he needs to be successful.

Look at the graph below to visualize the fade and run for his changeup. He aims to be in the lower-right quadrant, which reflects dropping fade and tailing run to right-handed batters. You can see that, this season, his changeups are in the lower-right “fade-run” quadrant.

Steele is even throwing changeups later in counts with two strikes, such as this strikeout below against Atlanta’s Travis d’Arnaud.

“Personally, I think his changeup is a real weapon, and I think it’s one you’re starting to see come out more and more confidently in games,” Hottovy said. “The way he’s learned how to throw it and how to keep the metrics in a good place on it without trying to manipulate it too much, I’m seeing his confidence continue to grow with that pitch in particular. I think it’s a weapon he’s going to be able to utilize toward righties.”

There’s also been clear intent behind when he’s thrown those changeups — heading into Thursday, all 20 this season have been to righties, exemplifying the fact he’s looking to give them a pitch moving away. By contrast, Steele had thrown 34 of 37 sinkers to lefties heading into Thursday; the intent has been to throw those batters a pitch running in.

“I think how I’m using it and when I’m using it and the amount I’m using it is what’s making it better right now,” Steele said. “For instance, to the lefties, I’ve been throwing it a lot inside to lefties. Especially lefties I’ve faced a lot, they know they can lean out over a four-seam away, slider away. Something that runs back in opens up the outer lane again. It’s like a small game of chess within the game.”

But the work isn’t done

While the usage of his pitches outside of his four-seamer and slider has increased, it’s not yet to the point that they are major parts of his mix.

Just look at Steele’s start Thursday night. Of his 93 pitches, 85 were either four-seamer or slider. He actually threw the curve six times, but he threw his sinker only twice and didn’t deliver a changeup.

There’s constant work being done both in between and on the day of starts on all his pitches, and finding the right balance in throwing them is important. For example, in a 30-pitch bullpen, Hottovy estimated 15-18 would be Steele’s top-two pitches; the rest will be a mix of the other three.

That’s all part of the process. The confidence to throw them in-game comes from the work that goes into developing them outside of game action.

“The big thing that we’re seeing every single time is the consistency in the shape, and when you see more consistent movement and consistent shapes, you start to trust them more,” Hottovy said. “… When you start working on them, getting them better and better, more consistent every time out, you start to trust them a little bit more. I feel like that’s where he’s at right now.”

Steele will continue to put that work in. He understands the two-pitch mix that brought him so much success last season may not keep him at that level forever.

He needs to continue adapting as a pitcher, and expanding the repertoire out again is what he believes will keep him on a successful path.

“When I start showing them different pitches, like show a two-seam that runs the other way or a changeup that fades the other way, it just puts in their mind, like, ‘Oh, he does have other pitches and he will throw them,'” Steele said. “That’s kind of the next step in my evolution.”