Tarik Skubal Has Arrived

With some insane strikeout rates during his short minor league career, all backed by mid-to-upper teen SwStk% marks and even an absurd 21.5% mark at Double-A in 2019, I have been excited about Tarik Skubal ever since he debuted last year. That performance was quite mixed, as he brought his strikeout stuff, punching out 27.6% of opposing batters, but also allowing a crazy 54.2% FB% rate, which is dangerous in our homer-happy times. Since he allowed an inflated 20% HR/FB rate, it resulted in a sky-high 2.53 HR/9 mark. It’s no wonder he sported an ERA near 6.00! Of course, his 4.12 SIERA suggested better days ahead, but all those fly balls are scary, nonetheless.

Still, the strikeout potential and significantly better SIERA made him a target in drafts and auctions this year, at least for me. Unfortunately, his April was so poor that I actually gave up on him in my shallow 12-team mixed league, but picked him back up for last week’s two-step and now plan to hold onto him for a while. Let’s compare Skubal’s April and May and learn why he’s now again looking like a strong fantasy asset.

Surface Metrics
April (4 GS) 17.3% 13.5% 3.8% 9.8% 0.238 82.1% 19.5% 5.98
May (5 GS) 34.2% 7.9% 26.3% 13.0% 0.333 89.3% 16.1% 2.98

Amazingly, Skubal posted just a 17.3% strikeout rate in April. Since pitchers change so frequently, I put a lot of weight on strikeout rate, even over smaller samples. If you’re supposed to be a strikeout pitcher and punching out less than 20% of opposing hitters over four starts, I assume something is wrong and am unwilling to stick around until that something wrong is corrected. Combine the lack of strikeouts with a double digit walk rate and you’ve got impending disaster. A 5.98 SIERA deserves to be nowhere near fantasy teams and it’s possible Skubal could have been demoted if he kept the poor rates up for another couple of starts.

Then when the calendar flipped to May, suddenly Skubal regained the form that made him a top prospect to begin with. His strikeout nearly doubled, his walk rate dropped well below 10%, and his SIERA fell just below 3.00. His ability to generate whiffs also improved dramatically, as his SwStk% surged from 9.8% to 13%. That latter mark is still well below his minor league rates, but it’s a welcome rebound.

Now let’s check out his Statcast metrics.

Statcast Metrics
Month EV maxEV Barrel% HardHit%
April (4 GS) 88.9 115.7 19.7% 36.6%
May (5 GS) 91.1 115.3 10.8% 47.7%

This is far more of a mixed bag than I expected to see! His overall EV allowed has actually risen by a meaningful amount! His maxEV is far too high and is nearly as high in May as it was in April. The good news is his Barrel% has been almost cut in half from an insanely high rate to just a merely higher than average rate. Also bizarre is his HardHit% has spiked in May. If all you had were these numbers, you would probably have no idea that his skills have improved dramatically in May, but the big drop in Barrel% is probably the most important number.

Now let’s jump to his batted ball distribution to see if there have been any changes.

Batted Ball Type Metrics
Month LD% GB% FB% IFFB%
April (4 GS) 20.0% 21.4% 58.6% 9.8%
May (5 GS) 16.9% 35.4% 47.7% 9.7%

Skubal continued his extreme fly ball ways in April and while he remained a fly ball pitcher in May, it hasn’t been to nearly the same degree. Fly balls are not as dangerous as they had been given the change in ball, but they could potentially lead to random implosions with multiple homers allowed. Still, this batted ball profile is much less scary than that in April.

Now let’s move on to the plate discipline metrics.

Plate Discipline Metrics
Month O-Swing% Z-Swing% Swing% O-Contact% Z-Contact% Contact% Zone% F-Strike%
April (4 GS) 21.5% 75.0% 45.8% 69.8% 81.7% 78.6% 45.3% 56.7%
May (5 GS) 31.2% 63.5% 46.3% 65.4% 75.5% 71.9% 46.7% 64.9%

Perhaps the ultimate indication of a pitcher’s stuff and command is Z-Swing%, with the lowest the rate, the better. The pitch is inside the strike zone, but the location or movement is just so good, batters can’t even pull the trigger and swing the bat. Skubal’s Z-Swing% dropped considerably in May, while his O-Swing% surged above 30%. That’s a delicious combination. He also reduced the contact rates on both pitches inside and outside the zone in May, further supporting the idea that his stuff was much better in May. Last, he has dramatically upped his first pitch strike rate, which has certainly helped improve on his walk rate.

Finally, let’s dive into his pitch mix. First, we’ll review his usage rates (Pitch Info).

Pitch Type Usage Metrics
Month FA% FS% SI% CH% SL% CU%
April (4 GS) 54.4% 13.1% 26.7% 5.8%
May (5 GS) 50.7% 3.4% 17.1% 20.5% 8.3%

Pitch Info suggests that Skubal has dropped a splitter and started throwing a changeup, but it’s possible the classification system has simply been tripped up as the two pitches are similar. Either way, the real changes look to be small increases in splitter/changeup and curveball usage at the expense of his slider. It’s a bit of an off change, especially considering his slider was graded at 60, representing his best secondary pitch. But it has actually generated a lower SwStk% than his changeup, first seen last year, and the gap has widened this year. I have no idea why he even throws his curveball, let along has upped its usage in May, as it has generated a lowly 4.6% SwStk% this year and 6.3% mark during his short career.

It doesn’t seem like pitch mix changes really explain how his performance has taken off in May.

So perhaps there was an increase in velocity? Let’s see.

Pitch Type Velocity Metrics
Month vFA vFS vSI vCH vSL vCU
April (4 GS) 94.2 85.4 85.7 74
May (5 GS) 94.6 94.1 82.1 86.3 73.7

Ehh, not really. There was a slight uptick in fastball velocity, but not enough to make a real difference. It’s interesting to see that his changeup is more than three miles per hour lower than his splitter, so perhaps it truly is a different pitch. So these velocity changes don’t tell us a whole lot either.

So after diving into all the metrics, it’s not totally clear why Skubal suddenly became the strikeout machine he was in the minors after a brutal April. His pitch mix didn’t change that much and he didn’t gain velocity. Perhaps it was a mechanical issue that got cleared up and he’s now able to match the way he had pitched and dominated in the minors. Since his April was the outlier and May closer to what his minor league numbers suggested, I’d lean closer to his May numbers as the real Skubal, though that doesn’t mean I would expect a 30% strikeout rate the rest of the way.

Whatever the reason, Skubal is now pitching like his minor league rates suggested his upside sat at. If you had dropped him and hadn’t realized he was making good on his promise in May, don’t wait any longer to pick him up!

Mike Podhorzer is the 2015 Fantasy Sports Writers Association Baseball Writer of the Year. He produces player projections using his own forecasting system and is the author of the eBook Projecting X 2.0: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. His projections helped him win the inaugural 2013 Tout Wars mixed draft league. Follow Mike on Twitter @MikePodhorzer and contact him via email.

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“Perhaps the ultimate indication of a pitcher’s stuff and command is Z-Swing%, with the lowest the rate, the better.”

While I theoretically agree with that statement over an entire season, I have to question its applicability over the course of a month, especially for a pitcher coming off a month with a 13%+ walk rate. It could mean that hitters are thinking they may be able to wait him out, and have yet to adjust to the fact that he’s throwing more strikes. I really think he deserved better than he got in April, that Whiff% wasn’t *that* bad, I think his surface numbers in May are more in line with the underlying numbers.

Free Bryan LaHair
Free Bryan LaHair

The key factor in Z-Swing in this context depends on percentage of strikes thrown in the given timeframe.

April 268 strikes 59.6%
May 304 strikes 64.8%

Considering this, I’d agree with Mike that a lower Z-Swing% is a positive thing, even in a months worth of pitches.


So this rate you’re presenting is basically strikes divided by total pitches, correct? It doesn’t really refute my point. A low Z-Swing% does not necessarily mean he’s “freezing” guys on pitches in the zone. It *can* mean that, but it doesn’t *always* mean that. For an extreme example, if you go 3-0 on a batter, but then groove a fastball on the fourth pitch and go out of the zone on your fifth pitch, your Z-Swing% would be zero, but it’s not a good indicator of stuff or control.

The league leaders (meaning lowest in this case) in Z-Swing% among qualifiers are Adam Wainwright, Joe Musgrove, Taijuan Walker, Austin Gomber, and Hyun-Jin Ryu. Not exactly a who’s who of stuff or control, necessarily. Jacob deGrom has the fifth highest Z-Swing% among qualifiers. The correlation between Z-Swing% and K% in 2019 was -0.125 and the correlation between Z-Swing% and BB% was -0.151 (min 100 IP), so a lower Z-Swing% actually would be associated with a higher walk rate. DeGrom finished with the second highest Z-Swing% that year.

I’m not necessarily saying that Skubal is not freezing people in the zone. I’m just saying that there is a lot that goes into a batter’s decision to swing at a pitch in the zone (count, pitcher’s control that day/in general, base-out state, looking for a ball to drive, etc.) that it’s dangerous to infer too much from that particular number.

Rollie's Mustache

It’s interesting to see that deGrom has the 5th highest Z-Swing% among qualified pitchers. There are always outliers but this feels weird given that he is basically prime Pedro right now.

Question for Mike (or anyone, really): How strongly does Max EV correlate to bottom line performance? Wouldn’t a Barrel-like metric that looks at % of pitches above a certain threshold be more instructive? (I’d rather give up one hit at 116 mph than several at 113, for example)