Examining Mike Soroka’s Arsenal

After an impressive 4.0 WAR season in 2019, 22-year-old right-hander Mike Soroka is set up to become the ace of the Atlanta Braves pitching staff. Soroka started all 29 games he appeared in last year and ranked 14th overall in FIP, with a 7.2 K/9 against a 2.1 BB/9 rate. Soroka induced grounders on over 50% of the contact he allowed, with a .206 GB BABIP (league average is .242 ). It’s a mixed bag of success when it comes to groundball pitchers, and Soroka ranked sixth overall in groundball rate last season (one spot behind his teammate Max Fried). Of the top 10 grounder rates in 2019, Soroka’s ERA was second to Hyun-Jin Ryu’s.

Soroka isn’t really a strikeout pitcher (142 strikeouts in 174.2 IP), but he does have a good mix of above-average pitches and velocity that keeps hitters wary. Soroka already does a pretty good job spreading out his arsenal, especially when ahead in the count and with hitters facing a two-strike count. Soroka’s repertoire has a few great pairing options, and if sequenced properly in the right game state, it could make the youngster dominant.

Let’s start by examining his arsenal. Soroka throws a two-seamer, a slurve, a four-seamer, and a firm, fading circle changeup. All four are demonstrated in the following isolated pitch overlay:

Soroka primarily throws his two-seamer, much more so when hitters have the advantage. He leans on the pitch much more to righties and takes advantage of its heavy run to jam hitters. When ahead in the count, he balances its use pretty well to left-handed hitters and splits the difference with his slider against righties. The pitch is also exploited more than his others, with hitters notching a 4.79 FIP and a .316 wOBA against it. While the wOBA mark is a bit below league average, Soroka’s inflated FIP is mostly due to his giving up home runs on 26% of fly balls. Given that his fly ball rate is just 13%, when he makes mistakes with the pitch, it causes a lot of damage.

Soroka turns to his slurve around 25% of the time and deploys it equally to both lefties and righties with good results. However, the pitch is much more effective to righties, as its combination of sweep and depth cuts away from a righty’s swing. It’s clearly his best pitch, with a 36% K/BB-rate and a 25 wRC+. Soroka goes to the slider consistently with two strikes, and draws strikeouts 25% of the time, with 32% of those strikeouts coming from pitches in the shadow or chase zones.

Soroka’s four-seamer is used just under 20% of the time; he favors it more to left-handed hitters, despite the fact that he gets better results when using it against righties (.155 wOBA vs .347 wOBA). The four-seamer has a high backspin component under a 12:40 spin direction and produces a good amount of lift. The slight axis tilt gives the pitch some run, which can be counteracted to an extent, given the small element of cut imparted by the sub-95% spin efficiency.

Lastly, we have the circle change. Soroka uses a four-seam grip on his changeup, which allows him to “disguise” it behind his four-seam fastball:

The pitch is used sparingly with a leaning towards left-handed hitters more so when ahead in the count. The heavy fade makes for a good chase pitch to draw strikes or keep hitters honest when they’re behind in the count. An hour ahead of his four-seamer, the pitch has a decent amount of rise due to the backspin imparted to it, which actually balances out with the fade created by the robust pronation at release.

Here’s a look at the natural shapes created by the design of each pitch using the Driveline EDGE tool:

Let’s take a look at Soroka’s frequent pitch combinations, with a minimum of four instances. I’ve included the league average metrics as noted in the tunneling research conducted over at Baseball Prospectus.

Despite a larger average release point separation, Soroka’s four-seamer and slurve are the ideal pairings in his arsenal. Note, however, that the back-to-back sinker to sinker combination appears to have better numbers. However, there is some risk in locating two of the same pitches closely together; the hitter may have missed or laid off the first time, but if the pitcher throws it again and locates closely to the previous pitch, the hitter may be ready the next time. The below-average PlatePreRatio numbers indicate that Soroka didn’t always keep the locations varied when double-dipping a pitch; this may be why the sinker wasn’t as effective as it could have been last year (4.79 FIP).

The slurve can break off its two-plane movement once the four-seamer’s run starts to take shape. In this case, the hitter’s eye level is broken up pretty well, as you can see the spread created by the location of the two pitches:

Another good option for Soroka is the sinker/slurve sequence, which, as we see from the chart, he indulged in quite often. The plate spread isn’t as large as it is with the four-seamer, but it’s still a well-above-average ratio. When both pitches are kept low, we can see that they break in opposite directions, almost symmetrically, as both pitches contain a fair amount of two-plane movement:

One combination that’s curiously absent from the group is Soroka’s four-seamer and changeup combination. Sequenced just four times total, they created a very tight tunnel (1.19 PreMax) and created a huge plate spread ratio (25.7 PlatePreRatio). While those numbers seem incredible, keep in mind they may have flattened out a bit had Soroka used them more. But the potential is clearly there. As mentioned earlier, the changeup bears a strong resemblance to the four-seamer because of the same seam orientation. Being able to counter one off of the other with an average velocity spread of 12 mph (the largest of any combination) could be a tremendous weapon for Soroka in the right circumstances:

Soroka’s stuff is enough to create a tough challenge for hitters in every at-bat. He should continue to deploy a balanced mix of pitches throughout all counts but be careful not to lean on his sinker as often as he did last year. Soroka has a few pitch combinations that can outwit hitters with their tunneling potential and resulting break. And while he won’t blow hitters away with his fastballs, he has the strategic means to circumvent opponents. Timing disruption, with velocity spreads and counteracting movement profiles, can be just as effective, and Soroka has that in spades.