Shapeshifting Lefties

I do love change. No, not that jiggle jiggle that my fellow kids and I love to talk about these days but simply the act of one thing turning into another. Change doesn’t have to be good or bad; it can be both, either, or neither. And perhaps nowhere is this more apparent than when looking at the arsenals of major league pitchers. More of this pitch, less of that one, more velocity here, less movement over there. More horizontal for that, less vertical for this, one fish, two fish, v fish, nu fish.

But just because a pitch changes how it moves, doesn’t guarantee the results will fare better, a quality that is already rather subjective when needing to factor in a pitcher’s intent that isn’t fully known. However, changes are useful flags and can serve as starting points. And when seeing dramatic movement changes in key pitches, I can’t help but wonder, why. We’ll take a look at two such pitches today, thrown by two left-handers who’ve had similar overall fantasy value in 2022, though, not quite of the top-tier variety. More like SP4/5’s that have 2/3 aspirations.

Jordan Montgomery, Sinker

Like our second contestant coming up later, Montgomery is a left-hander that’s coming off of back-to-back rotten starts but unlike Tarik Skubal’s offspeed dippery, it’s Montgomery’s shapeshifting sinker that makes our list, with the vertical movement increasing from the 49th percentile (vs avg) to the 71st percentile and the horizontal movement moving on up from the 77th percentile to a deluxe 98th percentile in the sky.

More like, swipe left, amirite?

But before we get to the present, let’s dip back to what Montgomery was working with last season. Like this perfectly solid sinker from 2021 that is located perfectly in Zone 9:

And here is a sinker from 2022, also located perfectly in Zone 9. But one of these things is not like the other:

It’s easy to go through and cherry-pick different sinkers from 2021 and 2022 to just show instances of good sink vs bad sink but speaking anecdotally after watching dozens of Montgomery sinkers, the extra 2+ inches of sink he’s averaging this season is a noticeable (and repeatable) difference. And the results against it have been palpable.

Not that good sinkers need more whiffs but any increase is appreciated, particularly given how low Montgomery’s whiffs against were most recently. A 9.3% SwStr% in 2022 puts him 10th among starting pitchers (min 200 sinkers thrown), while his 5.5% SwStr% from 2021 would’ve him squarely in the José Berríos/Martín Pérez part of sinker town. Plus, his CallStr% has only risen a point so the majority of the increase is coming from more whiffs. But while up it’s also not totally out of the ordinary, as the sinker posted a respectable 8.0% SwStr (n=199) in 2020.

Getting back to more sinkery things, the 54.2% GB% is up another four points after going up five points last season, however, that still only puts it just above average. But batters have done significantly less damage against it, posting a .278 wOBA (on contact) that is down from a .391 wOBAcon in 2021. Though, it probably shouldn’t be inspiring that the sinker has a .387 xwOBAcon in 2022 that is only down slightly from a .401 xwOBAcon.

Less damage, more groundballs, and more whiffs – it makes sense that Montgomery’s sinker has a -10 Run Value against it that leads his mix, with a -2.3 RV per 100 pitches that is nearly double the -1.2 RV/100 of the cutter in second place. And it’s not just leading his pitch mix, the same goes when comparing his sinker to the rest of the league. The -10 RV is tied with Framber Valdez for 1st among starters (and second only the ridiculous -14 RV of Clay Holmes) but the -2.3 RV/100 is about in a class by itself. It leads all starters, with Aaron Nola (-2.0 RV/100) and Chris Bassitt (-1.9) also sitting high but Sandy Alcantara in fourth is all the way down to a -1.4 RV/100.

But besides the actual results is how the big increase in sink (but without a loss in velocity) helps it to more closely mimic the movement track of a changeup that has been plus before and can be plus again:

And speaking of how well it works off his other pitches, giving him another effective weapon with which to work away from right-handers with, you know that I just can’t ignore that the sinker’s spin directions have changed from the previous two seasons, with both the observed axis (11:00 to 10:45) and spin-based axis (10:15 to 9:45) shifting, increasing the total deviation from 45 minutes in 2020/2021 to 60 minutes.

Not to always jumped to seam-shifted wake conclusions but it’s an easy one to come to in Montgomery’s case. His sinker is thrown nearly identical to how it was in 2021, in terms of its velocity (92.4 mph vs 92.6 mph, spin rate (2172 rpm vs 2205 rpm), and spin efficiency (89% both years). But something has helped its horizontal movement leap from the 77th percentile to the 98th percentile and SSW seems a likely culprit.

Sinkers might be the unsexiest option for examining movement changes but its new results are particularly important for Montgomery, who has always lacked a consistently strong primary fastball to back his excellent secondaries with. But the sinker’s new groove has ascended enough in 2022 to earn a spot as his mix’s backbone, with a 35% usage that leads all pitches and is up 14 points.

From a fantasy perspective, Montgomery is being held back by collecting just three wins for one of baseball’s best teams, failing to pick up a win in seven starts where he went at least 5 IP and allowed two or fewer earned runs but also a career low 18.7% K% that is down from 24.5% the past two seasons. But I’m willing to bet that those mid-20 ways will be coming back around soon, as his 13.8% SwStr% is (barely) a career best and is exactly where he was at in 2021. I also believe in the ratios, as Montgomery still has a 3.27 ERA (3.74 FIP/xFIP) even after getting lit up for 9 ER over his past 12 IP. And while a 1.02 WHIP is a career best by a large margin (1.23 WHIP in 2017) it is supported by a career-best 4.1% BB%, not to mention his primary fastball being a lot less hittable as it’s been in the past.

You don’t have to squint very hard to see more strikeouts and wins in his future, given his current whiff rates and supreme surrounding cast. He’s been a borderline top-50 SP so far but if those counting stats come and the ratios hold, Montgomery could be a second-half fantasy star.

Tarik Skubal, Changeup

After starting the month with seven innings of shutout ball versus Minnesota, Skubal has swooned in June, posting a 7.46 ERA over his past five starts. But that bloated ERA has been driven by an outbreak of too many home runs (1.42 HR/9 last five starts vs 0.31 HR/9 previous 10 starts ) and walks (3.9 BB/9 vs 1.5 BB/9). Given that, a 4.39 FIP and 3.91 xFIP over these last five starts isn’t unexpected.

But don’t get too stressed because bad months happen (plus, a schedule facing San Francisco, Boston, and Toronto doesn’t help) and Skubal was one of baseball’s best starters in May (1.45 ERA, 2.29 FIP, 30.4% K%). And while batters did extra damage in the month against most of his pitch mix, the changeup didn’t take the brunt of it, with batters still only posting a .255 wOBA (.278 xwOBA) against it in June.

Skubal’s changeup isn’t as heavily used as the rest of his mix (15% in 2022, almost exclusively to RHH) but the new and shapely version this season has ascended into his number-one finishing pitch, with a 33.8% PutAway% (up from 25.9% in 2021 and 18.9% in 2020) coming out well ahead of his four-seamer that is in second place at 19.6%. And considering how effective it has been this season, expect more of the same in the future.

To summarize the above: Skubal’s changeup owns his highest CSW% (by a lot), highest Chase% (by a lot), and his highest SwStr%/Whiff% (again, both by a lot). Mix in all of that strikeout candy with an above-average GB% and below-average damage on contact, and it’s understandable how the PutAway% has risen to the forefront.

The change in movement in 2022 has been stark, with Skubal throwing it slightly harder (83.7 mph vs 82.1 mph) but getting significantly more drop and break than before. Even with increased speed, the changeup is averaging 32.8 inches of drop in 2022 (up from 28.5 inches in 2022) and 13.9 inches of break (up from 8.7 inches).

While the increase in break has only gotten him up to barely above league average (0.4 inches vs avg, 48th percentile), that is a fairly dramatic change considering that in 2021 it sat in just the 4th percentile for horizontal movement, and was 3.9 inches below the league average for pitches thrown at a similar velocity/extension. But the increase in drop for this faster version is even more significant, going from 1.7 inches below average (30th percentile) to 2.4 inches above average that’s now in the top quartile.

Here’s Bryan Reynolds failing to handle that wiggle in:

And Jose Altuve has no chance against that wiffle wiggle heading out:

Wooo-oof. Good luck with that.

Throwing a faster changeup that moves more generally seems to be a good idea, especially when you’re backing it up with heaters that sit 94-95 mph but that can be run up to 97 mph+. And while it’s only used ~15% of the time, the changeup is serving as a righty-only offering that’s helping the young left-hander have continued success against the other-handers and keep him out of any splits issues.

Like Montgomery, Skubal has also been a borderline top-50 SP but unlike his left-handed peer, it’s hard to bet too heavily on more wins coming in the future, barring a dramatic turnaround for Detroit’s offense and/or bullpen. But unlike Monty in New York, Skubal’s elite velocity gives (and will continue to give) him a much higher ceiling. The changeup will need to continue being so effective but as much as anything, Skubal can’t be successful if he goes back to his high-walking ways. A 6.2% BB% in 2022 is still a career-best but we’ll need to keep an eye on whether his command troubles from June follow him into July.