New Cubs Star Shōta Imanaga Is Excellent Proof MLB’s Pitch Velocity Obsession Is Misguided

Imanaga throws his four-seam fastball at below league-average velocity, yet he’s still one of the most difficult starting pitchers a hitter can face.

Hitters haven’t been able to figure out Imanaga this season. / Kamil Krzaczynski-USA TODAY Sports

Among all the pitches thrown by all the pitchers in MLB, the best of them all is a below-average velocity, four-seam fastball. The 92-mph fastball from Chicago Cubs lefthander Shota Imanaga has the highest run value in MLB, even though it clocks in more than two clicks slower than the average heater (94.1).

Wait … what? How is that possible in an era when teams and pitchers chase velocity zealously while cooking up breaking balls with designer spin?

What is the magic behind the Imanaga fastball? It’s not magic. It’s physics, and it helps explain how the love affair with pure velocity is misguided.

First, a quick word about four-seamers. For more than a century they have been the bedrock of pitching, from Smoky Joe Wood to Sandy Koufax to Nolan Ryan to Clayton Kershaw. You threw four-seamers to get ahead to set up your secondary pitches. You threw them when behind in the count. You threw them at 3-and-2. You threw them to challenge weak hitters at the bottom of a lineup. Kershaw threw 70.5% four-seamers in 2010!

Those days are gone. Hard as it is to believe, the four-seam fastball, like hardcover books, concept albums and keeping score at the ballpark, sadly has fallen out of favor.

 

Four-seam fastballs are thrown less this season than at any point in recorded history (since 2008, which effectively means forever). But here’s the catch: they are thrown from a lower average release point and to a point higher off the ground than ever before. And they are harder to hit.

As I noted one month into the season, the Boston Red Sox are accelerating the change  in the game. Boston has played five games this year throwing no more than a handful of four-seamers. It has dropped its four-seam use from 26.1% last year to 15.4% this year. Back when four-seamers were a thing, the 2015 Tampa Bay Rays threw 49.3% four-seamers.

Meanwhile, to less fanfare than Boston, the Oakland Athletics have cut their four-seam use from 39.3% to 30%, the second biggest decline—and cut their ERA from 5.48 to 4.37.

While velocity may be good for depressing batting average and blowing out UCLs, it’s not the path to pitching success we think it is. Here are the six starting pitchers with the lowest ERA in MLB on Memorial Day and how they use the four-seamer:

MLB ERA Leaders, Four-Seam Use

Starting Pitcher	Pct.	MPH	MPH Relation to Average
Shota Imanaga, Cubs	58%	92.0	-2.1
Seth Lugo, Royals	24%	92.5	-1.6
Ranger Suárez, Phillies	20%	92.1	-2.0
Tanner Houck, Red Sox	0.1%	91.6	-2.5
Reese Olson, Tigers	24%	94.3	+0.1
Ronel Blanco, Astros	35%	93.6	-0.5

Five of the six best pitchers have below average velocity, with one right near the average velocity. Those pitchers change speeds, throw strikes and command the baseball, traits pitching coaches will tell you for a starting pitcher matter more than what the radar gun says.

The radar gun is to baseball what the landline phone is to communications: It still works but means less. What matters more are measurements such as Vertical Attack Angle, spin rate, ride and run. Data have helped teams learn what makes a good fastball, and it’s not just throwing hard or serving as the primary pitch to set up a breaking ball. Just as importantly, the data tells teams what a bad fastball is, which is why fewer teams are throwing them.

Pitchers will throw about 15,000 fewer four-seam fastballs this year than they did just five years ago. The quick decline in the pitch is amazing—but so are the results (2020 pandemic-shortened season not included):

MLB Four-Seam Fastball Use

Year	Pct.	Avg. Against	SLG. Against
2019	35.9%	.267	.486
2021	35.4%	.257	.455
2022	33.2%	.252	.430
2023	32.2%	.260	.456
2024	30.8%*	.243*	.412*

*Lowest in pitch tracking era (since 2008)

The decline in usage and increase in depressing slug (the No. 1 aim of pitching these days) is due to one factor: selectivity. If your four-seam fastball does not have elite properties, don’t throw it. Four-seamers have become harder to hit because we’ve weeded out the low-spin, thigh-high heaters pitchers would throw just because … well, just because that’s the way it always was done.

And forget about that folklore of “fastball counts.” One of the many reasons we are in such a difficult hitting environment is that pitchers would rather miss with a breaking or off-speed pitch than challenge with a fastball.

Just eight years ago, for instance, a hitter ahead in the count could expect a four-seamer 40.1% of the time. No wonder they hit .301 with such leverage. Today the hitter ahead in the count sees a four-seamer only 34.1% of the time and hits .272.

Two other huge factors within the usage trend are the height of the pitch and the release point. Four-seamers are getting elevated more while being thrown from a lower release point (2020 pandemic-shortened season not included):

Year	Height (in feet)	Vertical Release (in feet)
2015	2.57	6.05
2016	2.58	6.08
2017	2.63	5.96
2018	2.65	5.90
2019	2.70	5.94
2021	2.74	5.92
2022	2.81	5.88
2023	2.81	5.83
2024	2.82	5.83

Here’s what that means: within 10 seasons, the average four-seamer crosses the plate three inches higher and is thrown from a release point 2.1 inches lower. The lower-to-higher trajectory creates a higher Vertical Attack Angle, which confounds the hitter’s eyes and mind because it sinks less than most fastball paths the hitter has stored in the brain. As you can see, those trends are not abating.

That brings us to the beautiful science of Imanaga’s fastball. Imanaga is 5–0 with a 0.84 ERA, the lowest ERA after nine starts since 1913, when ERA can be tracked—better than the 0.91 of Fernando Valenzuela that stood for 43 years. The Cubs signed Imanaga for $53 million over four years—less per year than what teams paid Taijuan Walker, Jameson Taillon, Chris Bassitt and Zach Eflin the previous winter. More clubs should have seen the value in Imanaga. He is a premier strike-thrower with outstanding fastball properties and a wipeout splitter.

What makes his four-seamer so special? At 5'10", Imanaga throws his fastball with a low release point (5.49) and high spin rate (2,439 rpm), so it plays wickedly at the top of the zone. He has thrown 124 four-seamers in the top third of the strike zone and given up only five hits and a .119 batting average.

His heater has exceptional “ride,” which means it spins so fast it fights gravity (sinks less) than most fastballs. Among starting pitchers, only the fastballs of Cristian Javier of the Houston Astros and Kutter Crawford of the Red Sox have better vertical movement (in this case, holds its plane) compared to average. Hitters swing underneath it.

Imanaga belongs to a select group of pitchers who get outrageous spin off a low release point (2,400+ RPM):

Lowest Release Point with High Spin 4-Seamer

Pitcher	RPM	Vertical Release (in feet)	Avg. Against
Zack Wheeler, Phillies	2,406	5.32	.196
Freddy Peralta, Brewers	2,465	5.33	.243
Shota Imanaga, Cubs	2,439	5.49	.164
Jared Jones, Pirates	2,537	5.54	.235
Brandon Pfaadt, D-Backs	2,529	5.59	.211
MLB Average	2,292	5.83	.243

Wheeler is a great example of how four-seam pitching has changed. Since 2017 he has dropped his release point seven inches—and not coincidentally, the batting average against his four-seamer has dropped almost one hundred points.

The image on the left, below, is of Wheeler in 2017, with a four-seam fastball vertical release of 5.84 ft. and a batting average against of .291. On the right, Wheeler is pitching this season with a career low vertical release of 5.32 ft. and giving up a career low batting average against of .196.

Screenshots via MLB.tv /

Imanaga’s fastball is so good that he has yet to allow a hit with it with runners in scoring position (0-for-11 on 55 four-seamers).

Tremendous ride is only part of the story. His four-seamer also has above average horizontal movement. A fastball with elite ride and run is freakish. Among starters, only Imanaga and John Means of the Baltimore Orioles have elite ride and horizontal movement.

Such properties suggest Imanaga is a free-agent bargain with front-end stuff. There are, however, some warning signs. The more hitters see his unique stuff the more they will adjust. For example, hitters are batting just .152 against him the first two plate appearances in a game, but .347 after. He has allowed a .174 batting average through his first 75 pitches in a start and .333 after.

Also, at 5’10”, durability may be an issue. Imanaga threw 159 innings last year in Japan. Cubs manager Craig Counsell said the team will limit him to “170-ish” innings this year in the longer MLB season. (Kudos to Counsell for his honesty.) After rain washed out Imanaga’s start in St. Louis on Friday, Counsell seized on the opportunity to give him a breather. Imanaga will make his next start Wednesday in Milwaukee on 10 days of rest.

Is Imanaga’s amazing start sustainable? Not at a sub-one ERA level. Even Fernando faltered just as Fernandomania was building in 1981. After starting the year 8-0 with a 0.50 ERA through eight starts, he went 1-4 with a 6.46 ERA through his next eight starts.

Imanaga, though, has all the tools to continue to flummox batters. At 92 mph, with physics and command on his side, his four-seam fastball is as good as it gets these days. He is one of several pitchers offering refreshing proof that you don’t need to throw hard to be successful.