Shota Imanaga's Evolving Arsenal

[Jake Russell]

Monday night was the latest tough lesson in a long learning process, but The Philosopher has been making important changes all season.

Image courtesy of © David Richard-USA TODAY Sports

When the Chicago Cubs signed Shota Imanaga to a four-year, $53-million dollar contract in January, they certainly had high expectations. In fact, this contract may have been an underpay at the time–many thought Imanaga would get a much richer deal. In 2023, with the Yokohoma DeNA BayStars, he pitched to very good results–a 2.66 ERA in 159 IP, with 188 strikeouts, and, perhaps even more impressively, just 24 walks. He was an All-Star, and the Central League strikeout champion.

On the whole, Imanaga’s transition to Major League Baseball has gone very smoothly. Prior to a rocky outing in Cleveland Monday, in 123 1/3 innings, the lefty had a 3.06 ERA, a 22.0% K-BB% (the eighth-best mark among MLB starters), and 2.8 fWAR–which roughly translates to being worth $22.3 million. Imanaga is making just under $10 million this year; the contract has been a bargain thus far.

But, as is the case with many pitchers, Imanaga has had to constantly make adjustments to his game. As the league adjusts to you, and gets more information on you, you have to adjust back–and Imanaga has done exactly that to sustain his success to this point in the season.

On Apr. 1, Imanaga made his first MLB start against the Rockies, striking out nine, walking none, and giving up just two hits. He threw an astonishing 60% fastballs, a trend that continued the rest of the month. He threw 59.3% fastballs in April–61.1% to righties, and 55% to lefties. Granted, he had a 0.98 ERA during the month, but, again, as the league adjusts to you, you need to adjust back.

Since then, his fastball usage has steadily creeped downward, and his first two starts in August marked the first month that fastball usage has been under 50%. With that greater unpredictability has come a lot of whiffs, too.

Against righties, Imanaga has actually thrown more splitters than fastballs this month–splitter usage is up 20% from July against righties, and the pitch has drawn a whiff against opposite-handed batters on over half of swings thus far. On the contrary, his sweeper is not being used more than ever against lefties–although the pitch has had rousing success all season against same-handed batters, to the tune of a 42.4 whiff%. Yet, since the pitch peaked in prominence against lefties in June, it has steadily decreased.

The pitch is pretty rarely used, after all–its usage% is just 7%, despite it being his second-most-used pitch versus lefties. Maybe he is still trying to figure out the pitch's role. In August, he has already used it 7 times in two-strike counts vs lefties, a mark over 40%. And, since May, the usage is up over 35% in two-strike counts. The pitch certainly can help him be a whiff-getter versus lefties.

Imanaga has basically been a three-pitch pitcher, but all of this overshadows that he’s thrown five other types of pitches in games. It seems as if Imanaga has been experimenting with different pitch types and pitch shapes all season. He typically sprinkles in a few curveballs here and there–about three or four start, all to righties, Out of the 78 he has thrown this year, 63 have been in 0-0 counts–it serves as a “get-me-over”, change of pace pitch, that he’s able to land in zone at a 44% clip. That might need to change, eventually.

In May, he introduced a changeup, and by July, it was his third most-used pitch against righties. It’s very subtly different from his splitter–velocity is nearly the same, it just generates about 1.5 inches more of arm-side movement and about 2 inches more of vertical movement on average–a slightly different look, that can maybe help keep hitters off-balance. He's also utilized an altered grip with the splitter, at times.

Imanaga has even mixed in a few sinkers in August (it’s tied with his curveball for the 4th-most used pitch this month). And, of course, he threw that one very slow curveball to Paul Goldschmidt, that was supposed to be a change-of-pace type pitch.

The point in all of this is, it’s interesting to see how Imanaga’s arsenal has evolved throughout the year. Nobody expected him to throw 12 cutters this year, but it has happened. It fits his nickname, the pitching philosopher, that he has all these pitches that he mixes in here and there. Really, he throws about 3-4 pitches a game that aren’t one of his main four offerings. You never know what you’re gonna get from him.

I’ll say it again–in a league where everyone is always making adjustments, you have to adjust back. Imanaga may not exactly be a “kitchen-sink” type of pitcher, but as he begins to throw fewer and fewer four-seam fastballs and mixes in more and more secondaries, he might as well be getting there.

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[Billy62]

Shota has been one of the finest pitchers to wear a Cub uniform. Albeit, the sample size is small, and while it is too early to drawn comparisons to long-term Cub hurlers. The short sample while not being overly dominant, is every bit the equal of Jake Arrieta, Kerry Wood, Fergie Jenkins. Maybe a bit off the pace of Rick Sutcliffe's masterful performance in 84. Trying to get my mind wrapped around a 53-million dollar contract not being up to the standards of his worth, but that is todays ballgame. The point is that when Shota takes the mound, as a fan, I feel we have an excellent chance of winning the ballgame, and that is what its all about. 

[CubinNY]

the toughest lesson was that the umpires are painfully inconsistent and the worst possible time. There is no reason for this given the technology available. The game changed on the blown strike three call. I know "it's part of the game" and teams have to be able to overcome bad calls. But it doesn't have to be this way.