Shota Imanaga's Arm Angle is Back Up, Along with His Velocity

[Matthew Trueblood]

Image courtesy of © Rick Scuteri-Imagn Images

Shota Imanaga averaged 93 miles per hour on his four-seam fastball in his first outing of Cactus League play Tuesday. That was eye-opening for many, because Imanaga often struggled just to crack 90 MPH late last season. In most of his second-half starts, he averaged north of that number, but not by much—and he rarely even touched 92 or 93 miles per hour. On Tuesday, he lived right around 93 and touched 94. It's easy to imagine how that uptick in velocity might offer relief from the vulnerability to home runs that plagued him down the stretch.

Truthfully, though, velocity isn't a big factor for Imanaga. He got hit hard after his return from a hamstring strain last year, but that had much more to do with command and pitch shape than with speed. Whenever something gets out of whack for the southpaw, homers will be the source of the tsuris, because he lives on a fastball with deceptive rising action and a splitter that will get hammered if not well-executed and well-located. When he does have that ride on the heater and is commanding the splitter, though, he can have success even at 89-91 on the radar gun.

Alas, last season, Imanaga tried a mechanical tweak that didn't work. and it compromised the shape of his heater and the ability to throw the splitter with the action and the location that makes it play as well as possible. His average arm angle in 2024 was 40°, but in 2025, it dipped to 36°. The result was more run on the four-seamer, but (if anything) less carry, and a splitter that didn't tumble as steeply as it had in his excellent first season with Chicago.

On Tuesday, those shapes were back. Imanaga's stuff had more vertical separation, because the fastball was more consistently showing that ride. Here's a comparison between his start in Milwaukee last May (which he left with the injury that would sideline him for several weeks), and the one he had against the Padres this week.

Obviously, the splitter and sweeper also dropped less than did the fastball, but on balance, this is a better version of Imanaga. He can stretch the zone vertically more effectively this way, because he can more often tease the top of the zone with that fastball.

Imanaga's release point was also slightly higher Tuesday, and his release was closer to the center of the mound. We don't have arm angle data for spring games, but Imanaga seems to have raised his arm slot again. That's good news. Broadly, the league is trending toward lower arm slots, which lend themselves better to some forms of pitch design and deception. In Imanaga's case, though, throwing from a high three-quarters slot (but a low sheer release height, because of his diminutive stature and the way he drives down the mound in his delivery) maximizes the utility of his repertoire.

By no means is this a guarantee that the Cubs will have their 2024 co-ace back in full this season. However, it's a good sign that he appears to have corrected what amounted to a flaw in his mechanics, and that his arm is feeling so strong that he's already pushing the mid-90s in February. Imanaga looks likely to be a key contributor over the first stage of the season. On a staff that will try to protect key young arms and that won't have Justin Steele early on, that's exceptionally valuable. Imanaga's good first Cactus League outing was a major step toward a successful first month for his team.

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[Arlen]

So nice. Thanks again. (I'm a Packer fan and if they have another season like the last one, seems you're a fixture to be my more favored Matt in sports fandom.  ;-)