Resurgent Miles Mikolas returns to All-Star form.

While still pacing behind his 2018 performance (4.2 fWAR over 200 & 2/3 innings pitched), the 2022 version of Miles Mikolas has regained much of that Cardinals-debut season success, ultimately leading to his second All-Star Game selection. Given the state of disarray plaguing the St. Louis Cardinals' bullpen (outside of All-Star Ryan Helsley, of course), one could argue that Mikolas' value is actually understated considering he is averaging 6 & 2/3 innings per start over the course of 19 starts.


So what has changed for Mikolas during his resurgent first half of 2022?


It is pretty simple, actually: the effectiveness of the fastball (primarily, and my main focus of this post) and sinker; versus lefties, in particular.


In 2019, Mikolas was still valuable, but one cannot deny he took a step back from his 2018 All-Star performance. That season, lefties mashed both Mikolas' fastball and sinker, slugging .470 and .553 against each, respectively. Thus far in 2022, opposing lefties are "slugging" .143 and .254 against the two pitches. I use 2019 as the comparator season because that was Mikolas' last full season where he was considered, for the most part, healthy. The lost "season" of 2020 followed, and he started only nine games (44 and 2/3 innings) last year.


Is Mikolas simply reaping the benefits of one of MLB's best defenses in 2022? He is almost certainly benefitting from the defense behind him, as any pitcher would, but we also have Statcast's expected weighted on-base average (xwOBA), a statistic that tells us more about contact quality (the process) than just the typical slash line numbers of batting average and slugging percentage (the results). And sure enough, Mikolas' fastball is clearly suppressing contact quality more frequently in 2022 (.249) than it was in 2019 (.325). The same can be said about his 2022 sinker (.273) compared to his 2019 sinker (.373).


So what exactly has changed with Mikolas' fastball approach versus lefties thus far in 2022?

As you can clearly see, Mikolas has shifted the core of his fastball heatmap toward the middle of the plate, while remaining up in the zone. Also, despite a smaller sample size, the core is much tighter in 2022 than it was in 2019, indicative of (at least) one and/or two things: 1) better command and/or 2) a more deliberate plan of attack. Before we get into why I think the 2022 core is better for Mikolas' overall repertoire, let's take a look at two pitches thrown in their respective core locations.


First, on July 20, 2019, an up-and-in 92.8 mph fastball to Josh Van Meter was launched an estimated 353 feet over the fence for a two-run home run:

Compared to this lazy (88.2 mph exit velocity) fly out by Joc Pederson on May 5, 2022:

Up to this point, admittedly, everything detailed seems to be nothing more than lazy, results-based analysis, that may or may not be repeatable for post-All-Star break 2022. Living middle-up with a ~93 mph fastball surely cannot bring lasting success in 2022, right?


Frankly, I argue that it can, and I truly hope that this post can be a point of reference when we look back (fondly?) on 2022. Mikolas has made an MLB career out of tunneling the slider off the fastball (and sinker) or the fastball off the slider. I wrote about this (subscription required) back in 2018 when I was still semi-relevant at The Athletic St. Louis. With most MLB pitchers averaging 95+ mph, and our fourth year of getting to know Mikolas, his reliance on tunneling for success should surprise exactly no one.


And it remains a predominant tool for success thus far in 2022, as detailed perfectly by @cardinalsgifs in the following strikeout sequence of Christian Yelich on April 15, 2022:

The fastball is obviously not landing in the core displayed earlier in this post, but it is still up in the zone and is on the exact opposite side of the plate from where it was in 2019. Its placement on this side of the plate (and even more so when thrown to its heatmap core) allows for better tunneling of(f) the slider. Heck, it even disguises his high-arcing curveball better, but that's a detailed analysis for another day.


Whereas, when the fastball is thrown up and in, the batter can essentially assume out of the hand that it is a fastball because it is traveling at a wildly different shape than his breaking ball offerings. A slider out of the hand on the fastball path to Van Meter in 2019 would either hit him or travel behind him to the backstop. A curveball on that same path, too, would land on or behind him. If a left-handed batter is able to rule out both of Mikolas' pitches with downward and glove-side movement, then a 92 to 94 mph fastball possesses a high likelihood of traveling a long way, at high velocity off the bat.


To better understand this three-pitch sequence ending a nine-pitch battle versus Yelich, let's take a closer look at the paths of each pitch, frame-by-frame:

And the overlaid, scopic version of the sequence:

Back-to-back-to-back, these offerings are virtually indistinguishable at the decision-making point for Yelich. If you are having trouble keeping track of the pitches in the .gif, just think about facing them from Yelich's point of view.


Finally, if I have not yet convinced you of the tunneling impact of Mikolas' new fastball core, @cardinalsgifs cooked up yet another, never-before-seen .gif utilizing Baseball Savant's 3D pitch shape function:

When Mikolas hits the core of his heatmaps for the fastball and the slider (which happens regularly, hence the meaning of heatmaps), the offerings are essentially a perfect tunnel up to the batter's decision-making point. With this in mind, Mikolas' shift in fastball location has been a primary feature in his resurgence in 2022. If the Cardinals want to make a run to and through the playoffs, they will undoubtedly lean on Mikolas the rest of the way.


First and foremost, thank you to @cardinalsgifs for his tireless effort in putting together what makes this piece worth reading (I see you, @C70). Also, credit to FanGraphs, BrooksBaseball, and BaseballSavant for being valuable resources of data and video used in the creation of this post.