Hunter Greene was a phenom from a young age. He threw a fastball 102 MPH and was featured on the cover of Sports Illustrated when he was still in high school. Eventually, he was the second overall pick by the Reds in 2017 and thought to be a future star.
Then, arm trouble derailed his path to the majors. He finally debuted in 2022 and showed plenty of inconsistency and some more durability concerns along with tantalizing upside.
Everything came together this past season when he pitched his way to a 2.75 ERA as one of the most effective starters in the league.
Here, I’m going to talk about the adjustments he made on his way to breaking out, why they worked, and what to expect from him next season.
I’m writing these break out pieces every week. Check out how Tarik Skubal became the best pitcher in baseball from last week.
Out With the Old, in With the New
Greene mostly got by with raw talent during his first two seasons as a big leaguer. That’s not the worst plan when your starting point is an upper 90s fastball and devastating slider. Yet, his approach became predictable with such a narrow arsenal and pitched to a disappointing 4.62 ERA across 46 career starts through 2023.
He did show a changeup about 5% of the time along with the fastball and slider, but it was ineffective and unreliable. He threw it just 227 times over his first two seasons and opposing hitters teed off on it for a .333 expected batting average, .501 expected slugging percentage, and .358 xwOBA.
That pitch was finally trashed before last season in favor of a new splitter and the impact was immediate. Just check out the difference in results between the two pitches.
Here’s the eye test on that splitter too, just to be safe.
The improvement is even more stark considering he exchanged the changeup for splitters nearly one for one. He used each far more often against left-handed batters because right-handed batters had their hands full with the fastball and slider. So the off-speed stuff is reserved for lefties.
Still, it’s cool to see how he threw the different pitches in practically the exact same situations year over year. Here are his pitch usages for his changeup.
Now here’s his splitter.
The only real difference is significantly more trust throwing that splitter in two-strike counts, which we can chalk that up to it being more effective. Funny enough, the splitter was still wildly inconsistent, as many pitches are when they’re first learned, it was just so nasty that hitters didn’t have an answer.
It averaged 87.0 MPH with 1,202 RPM. That was the 11th hardest average velocity and 12th least spin for any starter’s splitter, respectively. The pitch also had less horizontal movement and more drop – or killed more ‘vert’ for you pitching nerds out there – than the discarded changeup. In turn, the Stuff+ jumped from 59 on the changeup to 120 on the splitter.
Also, it played much better off his fastball. Each had the exact same spin axis, meaning the spin of the two pitches looked indistinguishable to opposing hitters out of his hand. Greene talked about throwing the splitter like his fastball and how that mindset made it easier for him to learn.
With that, the two pitches could tunnel off one another and force hitters into more difficult decisions on whether or not to swing. His changeup did not have the same effect. Here’s a visual from Baseball Savant that can show this better than I can explain it. The top image is from 2023 and bottom from 2024.
Process, results, movement, models, and the eye test all agree that this splitter was a game-changer for Greene and a serious upgrade over his changeup.
Don’t Forget the Fastball
The splitter captured headlines regarding Greene’s breakout all season. Heck, it’s where I started too. How could you not? New pitches are fun and cool. Still, it’s possible changes he made to his fastball had a greater impact on his success.
Despite its blazing speed, Green’s fastball had a -12 Run Value in 2023. That was good for eighth-worst among starting pitchers. Last season, it was league-best at 20 RV. That remarkable turnaround came as its velocity fell from 98.3 MPH to 97.6 MPH (still very fast) and its usage rate held steady around 55% (nearly highest in the league).
So, what changed? Reds’ pitching coach Derek Johnson lauded Greene’s improved work ethic and routine last season. There was a motivation for him to fix his fastball which had no business being one of the least effective in the league. So, Greene got in the lab and fixed it. Take a look at these differences in his fastball shape, measured in inches.
He raised his arm angle ever so slightly which helped him to get behind the ball more. That let the pitch ‘rise’ more and run less. You can see his IVB – which means ‘Induced Vertical Break’ – jump up some and go from below league average to above it. That’s the rising action I’m talking about.
Often, increases in a fastball’s IVB will help them to miss more bats. Yet, the whiff rate on Greene’s fastball stayed right around 25% despite its new shape. Instead, hitters could no longer square the pitch up.
Damage Be Gone
One of Greene’s greatest hurdles to becoming an ace was never his talent, but his home park. Great American Ballpark in Cincinnati is the easiest park to hit a homerun in according to Baseball Savant’s Park Factors and third best place to hit in general, trailing just Coors Field and Fenway Park. Very few starters have grown into aces there (shoutout the legend, Johnny Cueto).
The problem compounded for a fastball-forward, power pitcher like Greene. Those archetypes often pitch up in the zone, which gives way to more fly balls, and trade some hard contact for more swings and misses. That can work in places like San Francisco or Miami. Just not Cincinnati, where Greene had a 5.13 ERA in 2023.
Everything changed last season with his new splitter and improved fastball shape. Now, hitters were getting way under the ball rather than squaring it up. Here are the differences in opposing hitters’ quality of contact against Greene over the last two seasons.
Truly night and day. We can take a look at Baseball Savant’s new Bat Tracking data to put this more succinctly: Greene was squared-up least often of any starting pitcher on balls in play and third-least on all swings last season. This data is new in 2024, so we have nothing to compare it to, but again, a night and day change from 2023.
Results
With these changes, Greene vaulted himself into a new echelon of pitchers. He had the fourth-lowest ERA, 10th highest strikeout rate, and seventh-lowest WHIP for any pitcher who threw at least 150 innings. With that, he was the 14th ranked starting pitcher in fantasy baseball last season according to FanGraph’s Player Rater.
(He also had the lowest ERA for any Reds pitcher not named Johnny Cueto since Great American Ballpark opened in 2003).
Those 150 IP were critical, too. It was the first time Greene had ever crossed that plateau as a professional and he only got there by the skin of his teeth after hitting the injured list with elbow soreness in August.
Everyone held their breath with that diagnosis. Greene already had one Tommy John surgery in the minor leagues and a second would’ve been nothing short of a disaster. Thankfully, he was able to return after about a month and pitch seven innings with seven strikeouts across two September starts to end his season normally.
What’s Next
Let’s just say I’m… curious how all these improvements for Greene hold next season. There’s plenty of question as to how much control any pitcher has over their opponents’ quality of contact, let alone one uses a barrage of high fastballs in the league’s smallest ballpark who just went from the bottom of the league to the top in limiting hard contact.
All of the underlying stats show that his results can be trusted to a degree, but Greene’s home run to fly ball ratio fell to 6.9% in 2024. That is less than half of his career average and almost five percentage points lower than the league average. Again, that’s even more shocking when you think about both how Greene pitches and where he pitches.
On the other hand, the draft market seems to be already baking in some regression and general injury risk here. Greene is being taken as the 25th starting pitcher off the board in early drafts, between Freddy Peralta and Tanner Bibee.
They’re all in this glut (or “The Glob” as Derek VanRiper so eloquently puts it) of starting pitchers between picks 60 and 130 – or Pablo López to Jared Jones – that you could convince yourself are all possible SP2’s with moderate SP1 upside if things break right.
That price tells me Greene is still a value. The pure desire he showed to improve over the last year tells me his work isn’t done. What if his curveball becomes a real weapon? Or maybe the splitter takes another step forward or his command improves across the board. The foundation is so strong that any more incremental improvement, even with mild regression, could turn Greene into one of the best pitchers in baseball.
