How a 92 mph fastball became MLB's most valuable pitch

The most valuable pitch in baseball in 2024 is a 92 mph fastball. That seems impossible. But Shota Imanaga is showing the Major Leagues that velocity is just a number.

The start to Imanaga's MLB career has been incredible. Entering his seventh start of the season Tuesday against the Padres, the Cubs left-hander sports a perfect 5-0 record, a sparkling 0.78 ERA and 35 strikeouts.

And maybe the best part is that the 5-foot-10 Imanaga is dominating with a "heater" that sits two whole mph slower than a typical fastball in this day and age.

• Imanaga leads latest Rookie of the Year poll

The average MLB four-seam fastball velocity in 2024 is 94 mph. Imanaga's is only 92.1 mph. He's in the bottom quarter of the league in fastball velocity. And yet, that fastball has been worth as much to the Cubs this season as any pitch thrown by any pitcher in the Majors.

"I just have to make sure I'm not throwing lazy fastballs," Imanaga said via Cubs interpreter Edwin Stanberry after his last start, when he shut out the Mets for seven innings. What Imanaga doesn't have in velocity, he makes up for in the intent behind every pitch he throws. And the results speak for themselves.

Most valuable pitches in MLB in 2024
Entering this week

• Shota Imanaga's 4-seamer: +9 runs prevented
• Tyler Glasnow's 4-seamer: +9 runs prevented
• Corbin Burnes' cutter: +8 runs prevented
• Luis Castillo's 4-seamer: +8 runs prevented
• Hunter Greene's 4-seamer: +8 runs prevented
• Javier Assad's sinker: +8 runs prevented
• Ryan Pepiot's 4-seamer: +8 runs prevented

Look at the other four-seamers on that leaderboard, which takes the result of every pitch thrown and measures its impact on run scoring. Glasnow's averages 96.3 mph. Castillo's averages 95.3 mph. Greene's averages 98.0 mph. And yet, there's Imanaga's 92.1 mph fastball, right there at the top.

• Execs consider Imanaga signing one of offseason's best

How does that happen? There are two key reasons:

1. Imanaga throws one of the best rising fastballs in the Majors
2. Facing Imanaga also comes with the threat of his unique lefty splitter emerging from the shadow of those fastballs

"It's a result of just thinking about: 'How can I get to the level of MLB pitchers?'" Imanaga told MLB.com. "I know that, for me, it's gonna be hard to beat them based on velocity. So if I have something else where I can, not even necessarily try to get ahead of them, but just be even with them. That's what I want."

Let's dive into those two driving forces behind Imanaga's lights-out run. Here's how a soft-tossing lefty is outpitching even the top fireballing aces in the Majors in 2024.

1) The elite rising fastball

Velocity is great, but it's only one of the characteristics that matters for a fastball. And Imanaga has one of the other big ones: Rising action that makes his fastball play up above its velocity.

There are two ways to look at the "rising fastball" effect Imanaga creates (which really means that his fastball drops less than a hitter would expect, which results in bad swings).

First, there's Statcast's fastball movement leaderboard, which looks at how much rising movement each pitcher generates vs. others who throw comparable four-seamers, with similar velocity and release point profiles. Imanaga's fastball has top-five rise vs. his MLB peers by that barometer.

4-seamers with the most rise above avg., 2024
Pitchers with 100+ 4-seamers thrown

1. Alex Vesia: +4.1 inches
2. Kutter Crawford: +3.6 inches
3. Shota Imanaga: +3.4 inches
4. Cristian Javier: +3.3 inches
5. Triston McKenzie: +3.1 inches

Second, we can look at Imanaga's induced vertical break, which, for fastballs, measures how much total rise a pitcher creates from the way he spins the baseball. Imanaga's four-seamer generates 19.3 inches of rise via IVB, which is top 10 in the Majors in 2024 -- just ahead of rising fastball king Justin Verlander.

Imanaga releases his four-seamer from a low slot, with a high spin rate (2,424 rpm), and most importantly, with true backspin, which means nearly all of his fastball spin contributes to the rising movement of the pitch. (He has 99% spin efficiency, among the highest in MLB.) His fastball resists gravity longer than one without that backspin would, and as a result, hitters think his fastball will end up in a lower location than it does. That's the first big reason why they don't hit it, even when it comes in in the low 90s.

"I've been pretty focused about trying to throw it into the zone, just kind of learning that it is OK to do that," Imanaga said.

Imanaga's "rising fastball" profile is why the Cubs have been encouraging him to throw his four-seamer at the top of the zone since he arrived from Nippon Professional Baseball -- that's where a rising fastball will often work the best against Major League hitters. And Imanaga has elevated his four-seamer almost 60% of the time, which is significantly more than most starters and a shift from how pitchers tend to attack hitters in NPB, where high fastballs are less common.

"With the data on myself, there's not really that big of a difference from here to Japan," Imanaga said. "I will say there's better data -- not necessarily more data -- against the hitters. It's a lot easier to see [what's effective]."

Imanaga's four-seamer doesn't generate huge swing-and-miss numbers (his whiff rate is 21.2%), but opposing hitters are batting just .137 against it. That's the fourth-lowest batting average allowed by any pitcher with at least 50 plate appearances decided on his fastball.

"The main thing that I'm trying to get out of my fastball is to try to get the hitter's contact point a little off," Imanaga said.

But make no mistake, he can and does use his fastball to get the K. His fastball does beat hitters -- that's how he struck out Shohei Ohtani in their showdown on April 7. Imanaga's 17 strikeouts on four-seamers are among the most for a starter with below-average velocity, and only Nestor Cortes has lower velo than Imanaga with more K's.

Most 4-seam K's by SP averaging under 94 mph in 2024

• Kyle Harrison: 29 (93.0 mph)
• Jack Flaherty: 20 (93.8 mph)
• Nestor Cortes: 19 (91.5 mph)
• Joe Ryan: 19 (93.6 mph)
• Chris Paddack: 19 (93.9 mph)
• Shota Imanaga: 17 (92.1 mph)

2) The rare lefty splitter

Imanaga's fastball is good on its own, but it's even better because of his splitter. When the threat of the splitter is looming alongside his heater, hitters have a hard time doing any damage against either pitch.

The fastball-splitter combo is at its most baffling when Imanaga gets ahead -- which he does all the time.

Imanaga relies heavily on his four-seamer to start at-bats, and he's extremely fastball-heavy if he falls behind. But that rarely happens. Imanaga gets ahead at one of the highest rates among starting pitchers -- he's been ahead in the count for over a third of the pitches he's thrown in the big leagues.

And once he gets ahead -- and even more so with two strikes -- you don't know what's coming, fastball or splitter.

"I'm really more focused on the hitters trying to wait for a fastball, then throw a splitter," Imanaga said.

In the chief putaway counts -- 0-2, 1-2 and 2-2 -- Imanaga's split between four-seamers and splitters is basically even. Which is why he gets about the same number of strikeouts on each pitch (17 on four-seamers, 16 on splitters) even though his splitter is more of a pure swing-and-miss pitch than his fastball, with a 43.4% whiff rate.

"In order for me to win, I think that [mix] is really important," Imanaga said.

His command over both pitches goes a long way toward his success with his arsenal. Imanaga's four-seamer and splitter are released almost identically -- they spin in the same direction, and start on the same trajectory -- but there's almost no overlap in where they end up.

Imanaga's four-seamers rise to the top edge of the strike zone, and his splitters -- which come in nearly 10 mph slower at 83.2 mph, with less than half the spin of his fastball at 1,097 rpm, and drop almost two feet more -- tumble to the bottom edge of the strike zone.

Combined, they fill every part of the zone, but each pitch type is concentrated in the region it is most effective.

"I think, for me, if I throw it in those locations, it's the lowest risk," Imanaga said.

Then there's the uniqueness of the splitter. Imanaga's four-seamer is deceptive because of its rise. His splitter is deceptive because Major League hitters just aren't used to seeing a lefty splitter.

The splitter revolution might be coming to the big leagues -- and the splitter has long dominated Japanese baseball -- but in MLB, a splitter from a left-handed pitcher is still exceedingly rare. Left-handers typically throw traditional changeups as their offspeed pitch. Not Imanaga.

Before 2024, no left-handed starting pitcher had regularly thrown a splitter in Major League Baseball in six years -- not since Aríel Miranda in 2017 -- let alone an upper-echelon lefty starter.

Tarik Skubal, who might be the best lefty in the Majors today and has one of the nastiest changeups, tested out a splitter in 2021. He scrapped it after a month. Clayton Kershaw, one of the greatest southpaws ever, toyed with a split-change last season after a decade and a half of a changeup eluding him. He threw a grand total of five.

LH SP with 100+ splitters thrown in an MLB season
Pitch-tracking era (since 2008)

• Shota Imanaga -- 2024
• Aríel Miranda -- 2016-17
• Jorge De La Rosa -- 2008-11, 2013-16
• Erik Bedard -- 2013-14
• Manny Parra -- 2008-10
• Randy Johnson -- 2008-09

Now Imanaga's out there throwing his splitter 29% of the time, as his No. 1 swing-and-miss pitch. Having a weapon that Major League hitters just aren't used to seeing to pair with his already deceptive fastball just makes Imanaga even tougher to face.

"Personally, I don't think about it as an advantage," Imanaga said. "It's just something that I know is unique to me. So if the people around me can figure out the advantages of that, that's great."