Kamil Krzaczynski-USA TODAY Sports
Among the crowd of high-end starting pitchers to sign with new teams over the offseason, perhaps none had wider error bars surrounding his projection than Shota Imanaga. An NPB star for the past half-decade, Imanaga had a track record of success but also many questions about how his skills would translate to MLB. This certainly is reflected in his contract with the Cubs, which came with just two guaranteed years worth $23 million, a far cry from our $88 million estimate. But for the past month and change, the 30-year old rookie has been up there with the league’s best.
Shota Imanaga’s Stat Rankings
- K%: 18th
- BB%: 4th
- ERA: 1st
- xERA: 4th
- FIP: 8th out of 79 qualified pitchers
Through his first seven starts, Imanaga has allowed just five earned runs, fewest among qualified pitchers. He’s been downright dominant through much of this stretch, proving his stuff is up to major league standards while controlling the strike zone better than almost anyone else. But he’s done so differently than other top pitching talents. Let’s take a look at his pitch arsenal.
From a quick glance at the stat sheet, the first thing that catches my eye is the sheer frequency with which Imanaga uses his fastball. In an era where nearly two-thirds of starters throw non-fastballs a majority of the time, Imanaga’s 58.4% usage (91st percentile) stands out. As pointed out by MLB.com’s David Adler, Imanaga’s heater has been the best individual pitch in baseball by run value, beating out Corbin Burnes’ notorious cutter Tyler Glasnow’s frightening fastball.
But while the other heaters at the top of this list sit in the mid- to upper-90s, Imanaga’s four-seamer averages just 92 mph. The list of starters who sit at 92 or below is rather short, and mostly consists of names that we certainly don’t think of as strikeout artists. In his piece, Adler noted that Imanaga’s fastball has elite induced vertical break (IVB).
Because of its low release point and high carry, Imanaga’s four-seamer has the third-shallowest vertical approach angle in baseball, creating the deception that causes batters to swing under it with surprising frequency. Its 12.5% swinging strike rate and 22.1% putaway rate easily exceed the league averages of 10.3% and 17.9%, respectively, as he’s able to throw it for a whiff in any count.
To be the most valuable pitch in baseball, Imanaga’s fastball has to work even when he’s not blowing it past hitters. And at first glance, you might think that a low-90s heater that lives in the zone would get sent a long way when batters connect with it. Indeed, homers were the one knock on Imanaga’s game in NPB, as his 2.9% homer rate (1.04 HR/9) last year was highest in the league in a deadened offensive environment. But he’s allowed just three homers across his seven MLB starts, and the Statcast data indicate this low total is more a product of skill than luck.
I’m not saying that a 0.65 HR/9 represents Imanaga’s true talent (ZiPS forecasts a 0.94 mark for the rest of the year), and it’s certainly likely that the results will regress toward his xwOBA as the season goes on, but he’s clearly been keeping pitches away from barrels at an above-average clip, a skill that many evaluators were skeptical of as he made the leap to MLB.
Imanaga also locates his fastball in places unlikely to produce barrels. Sure, he throws more heaters in the zone than almost anyone else, but he’s not just sending them down Broadway and hoping for the best; instead, he’s consistently hitting his spots at the top edge of the zone. He ranks 10th in fastballs thrown in the upper third of the zone, an area where the flatness of the pitch can play up and create the illusion that it’s rising.
Imanaga’s fastball alone has made him one of the most effective pitchers in the league, and I haven’t even talked about his plus splitter yet. Like the fastball, this is a pitch he throws with remarkable accuracy. Splitters are hard to command – many pitchers’ splitter heatmaps look like giant blobs, and nearly 14% of splitters are wasted, the second highest of any pitch type. But Imanaga repeatedly hits the area at the bottom of and just below the strike zone, an optimal spot for success.
Thrown from the same release point and angle as his heater, Imanaga’s splitter gets hitters to swing at what they think is a meaty fastball before they have time to realize that the pitch is 9 mph slower and 19 inches lower. He throws it only about half as often as his heater, saving the split for two-strike counts where hitters are in swing mode. And swing they do, coming up empty nearly half the time they offer at it.
The splitter has also been integral in maintaining Imanaga’s minuscule walk rate, as hitters swing and miss at them before they can work themselves into deep counts. Opponents have swung at 47.2% of the out-of-zone splitters he’s thrown, a huge reason his overall chase rate nearly tops the charts. His low walk rate and refusal to waste pitches has worked wonders in terms of efficiency, averaging the sixth-fewest pitches per inning among qualified starters. Imanaga’s quick work of opposing lineups has allowed him to pitch deep into games (averaging six innings per start) while acclimating to more frequent outings as part of a five-man rotation. Just a month…
