The Kansas City Royals had the fifth pick in the 2012 June amateur draft and selected a converted pitcher from the University of San Francisco named Kyle Zimmer, a one-time third baseman who was considered a bit undersized yet possessed a lively arm. That assessment caused Zimmer to give pitching a shot in order to get some of the playing time that would surely be scarce for him as a fielder. That decision ultimately turned Zimmer into one of the best pitching prospects in amateur baseball.
Zimmer also brought a high level of competitiveness that he’s maintained throughout his career. Unfortunately for the organization, Zimmer would prove to be very injury-prone and his road to the big leagues would be an arduous one. Over time, Zimmer began a slow walk towards the gates of the ‘never-was’ pitching prospects; a path that could be considered self-inflicted as he had the propensity of trying to play through pain.
Despite all of Zimmer’s floundering, the Royals weren’t ready to give up despite knowing that his injury history has a high probability of repeating itself. At the encouragement of GM JJ Picollo, Zimmer visited the touted Driveline Baseball facility in Seattle last summer. The hope was that Zimmer could have similar results as the Cleveland Indians’ Trevor Bauer has shown during his time at the facility.
The Athletic KC’s Rustin Dodd wrote of Zimmer’s first recorded throw at Driveline- a 58 MPH fastball. It was clear Zimmer’s rehabilitation would require a careful approach. Nevertheless, Zimmer put in the work and got himself back to where he needed to be in order to compete for a roster spot during the spring of 2019. The Royals brought him back on a Major League contract to see what he could do.
Beginning the high-intensity phase of throwing rehab for @kylezimmer11. From ~58 MPH with pain to MPH with none. Still a long road back; the mound comes in a week or so as workload capacity is built.— Kyle Boddy (@drivelinebases) August 18, 2018
Next tweet details the steps the last few months have looked like. pic.twitter.com/8iWSVVqpFW
While expecting Zimmer to turn into the next Trevor Bauer would be a lot to expect, Zimmer showed signs of promise this March. Its a very small sample, but an appealing one all things considered. Maybe Driveline has rebuilt another career.
As a testament to Zimmer’s resiliency and determination, he had an outstanding spring. Along with a stellar 0.71 ERA and 0.95 WHIP, his opponent quality, according to Baseball Reference, is 7.9. That indicates he’s facing pretty good talent and we can (for the most part) take his performance seriously. Through 17 1⁄3 innings and 46 batters faced, Zimmer’s K/BB rate is 5.3 (21 strikeouts/4 walks). That’s the kind of ratio you want in a relief pitcher.
Zimmer has shown good control and he is throwing his pitches in an effective manner. Patrick Brennan, founder of Royals Farm Report and contributor to Beyond the Box Score, laid out Zimmer’s pitch sequences from a March 15th bullpen appearance.
Kyle Zimmer's 15 pitch inning— Patrick Brennan (@paintingcorner) March 15, 2019
96 MPH FB ball
96 MPH FB foul
78 MPH CB ball
96 MPH FB SwStr
96 MPH FB GO
77 MPH CB strike
89 MPH FB foul
96 MPH FB ball
81 MPH CB SwStr (SO)
94 MPH FB SwStr
78 MPH CB ball
79 MPH CB strike
96 MPH FB foul
80 MPH CB ball
97 MPH FB (!!!) strike (SO)
Zimmer has done a great job mixing his three pitch arsenal this spring. Here’s an overlay of the above outing featuring all three of Zimmer’s pitches.
The most exciting aspect of Zimmer’s resurgence is that of his pitch velocities. Both his changeup and curve have gained 2 MPH and his fastball, which has sat around 96 all spring, is a good 3 MPH faster that his career average. Take a look at him blowing a low fastball by San Francisco Giants’ Travis Shaw.
While it all seems to be coming up roses for Zimmer, there isn’t an absence of concern.
Zimmer’s fastball movement might be an issue for him. He has little to no ride on the pitch but that isn’t necessarily a bad thing so long as you have good command of the pitch. On the other hand, he does get some decent vertical break and he still can fire it in well above league average. Velocity aside, a fastball without much life is barreled contact waiting to happen. That’s especially so when you’re working with a limited set of pitches. As mentioned earlier, he has his sequencing down pretty good and his other two pitches (which includes a random changeup) create a sizable velocity spread.
Nimble fastball aside, Zimmer’s best weapon is his curveball. He can dip it high in the zone or make the bottom drop out mid-zone. In the example below, Zimmer’s curve does what is referred to as a ‘bunny hop’ (a phrase I’m stealing from The Athletic STL’s Joe Schwarz). Zimmer is creating a ton of spin on the pitch, most of which is referred to as ‘useful spin’ as evidenced by how sharply it breaks.
As you can see, Zimmer isn’t throwing a curve, he’s spinning the curve. There’s a big difference.
Now an example of how Zimmer can manipulate his curve to create a ‘fall-off-the-table’ break by adjusting the velocity with his spin, the concept of which relies on the Magnus effect (more info on curveball spin here).
Zimmer has also made adjustments to his mechanics, especially in regards to release. Take a look at his 2019 release points in comparison to the rest of his career.
Notice the cluster to the left and the clump to the right. The latter is from this spring and we can see they are much tighter and linear than in the past. As far as his early performance is concerned, it seems to be immensely helpful.
Let’s go back to his movement profile for a minute. You can see from the chart below that there is minor horizontal movement between each of Zimmer’s pitches.
His fastball is almost dead center while there is a little arm-side movement on his changeup and the same can be said of his glove-side curveball.
Zimmer’s changeup is a bit troubling as well - there is little which separates it from the fastball besides velocity. The league-average velocity difference between the two pitches is about ten miles per hour. For Zimmer, its closer to six. The two don’t seem to behave much differently, either. Remember how I spoke of the vertical movement on his fastball, and how it generates almost no ride? When he turns to the pitch, Zimmer will need to be very careful how he sequences and should only be using it sparingly (for now).
In order to make it a more effective pitch, he’ll need to adjust the spin rate to create more break/movement and possibly give its spin axis a tweak. I’d like to see another 6-7 inch drop before I’d be OK with him throwing it more often. That will also further separate the change from his fastball.
Even without much use for the changeup, the curveball-fastball combo will work well for Zimmer. In relation to his fastball, there is a huge amount of vertical drop coming out of the the same arm slot. When the ‘hop’ that I discussed earlier is present, it will require Zimmer to keep his fastball up in the zone if he wants to create tunnels.
Take a look at this gif below using the curve and fastball from the earlier three-pitch overlay to get a better idea of how the duo play off each other.
It’s not an idea tunnel since there is a bit of separation due to the roughly 15 MPH difference but you can see how they follow a similar trajectory until they break apart at the tunnel point (about 150 ms after release).
Here’s another view were Zimmer is creating both (elusive) arm-side run on his fastball and glove-side break to his curve. Our angle isn’t the best but this is the ideal pitch ecosystem for Zimmer.
Zimmer isn’t without flaws and given his injury history, we should tread lightly on expectations. He’s shown us a flash of what he could be at the top of his game but that all hinges on his arm health. Perhaps his summer conditioning in Seattle has reformed him or, at the very least, make him more cognizant of his arm issues and when to listen to his body. It has definitely changed his approach on the mound and if the stars align, Zimmer has a serious shot at being a top-notch bullpen arm in 2019.
Zimmer should absolutely be included in the Opening Day roster. It would be a big shock if he’s sent to Omaha. While on the surface it might not be such a bad idea to give him some more time to get ready for regular big league hitting (he’s pitched less than 50 MLB innings since 2016). However it would be a travesty if an injury befell him before he had a chance to prove himself worthy of the number five overall pick some seven years ago.
Zimmer has the goods and deserves the opportunity to show Royals fans the promise he displayed in what seems like ages ago.