Grading the Pitches: 2016 AL Starters’ Curveballs

Previous: AL Starters’ Changeups / NL Starters’ Changeups.

Sample sizes are building, but not nearly to a size worthy of deep analysis, so let’s keep rolling with our pitch-specific analysis of the arsenals of 2016 MLB ERA qualifiers. Last week, we looked at the best changeups in both leagues. This week, we’ll examine curveballs. Today, it’s the American League’s turn.

We’re giving all of the offerings a letter grade, weighted 50% on bat-missing and 50% on contact management. League-average range performance in both component measures would receive a “B” grade. If that seems high to you, bear in mind that these are already better-than-average pitchers, simply by virtue of their ability to compile the 162 innings necessary for qualification while dodging the not insignificant hurdles of injury and ineffectiveness.

Let’s start it off with a table that will serve as the backbone of our analysis:

2016 Pitch Grades – AL Qualifiers’ Curveballs
Kluber 70 27.0% A 19.5%
Porcello 53 7.6% B+ 13.9%
Verlander 62 7.9% B+ 25.3%
Nolasco 59 11.0% B+ 11.0%
Fiers 63 8.9% B+ 19.0%
McHugh 80 17.6% B+ 29.9%
Bauer 79 13.6% B 18.9%
Sanchez, Aa. 80 14.6% B 16.2%
Quintana 83 11.3% B 24.6%
Duffy 92 15.2% B 23.9%
Tomlin 99 13.2% B 15.0%
Fister 99 14.3% B 14.7%
Weaver, Jr. 106 13.0% C+ 20.9%
Ventura 109 14.4% C+ 25.3%
Perez, M. 111 10.3% C+ 11.7%
Miley 111 8.8% C 12.1%
Estrada 124 7.6% C 10.6%

The first column contains each pitcher’s pitch-specific Adjusted Contact Score. Here’s some brief background for those of you unfamiliar with that concept. MLB average production was applied to each ball in play based on its exit-speed/launch-angle combination. Total production of all BIP was then scaled to 100. Below 100 is good; above 100, not so much.

The second column includes each pitcher’s pitch-specific swing-and-miss rate. The last column indicates the pitch’s usage as a percentage of their overall pitch count.

Color-coding is used above to note significant divergence from league average. Red cells indicate values that are over two full standard deviations above league average. Orange cells are over one STD above, yellow cells over one-half-STD above, blue cells over one-half STD below, and black cells over one STD below league average. Ran out of colors at that point. Variation of over two full STD below league average will be addressed as necessary in the text below.

The assessment of each letter grade was a somewhat subjective exercise. With “B” considered league average, I estimated each color-coding bucket to represent a half-grade move above or below average. The final letter grade involved splitting hairs very tightly in some cases.

Last week, I fawned over what an effective pitch the changeup can be. Well, the curveball is almost in its league. Both had above-average swing-and-miss rates (CH = 15.3%, CU = 13.5%, within the population of MLB ERA qualifiers). Both were also substantially above-average contact-management offerings (AL qualifiers’ CH = average 83.1 Adjusted Contact Score, CU = 87.1). The color-coding above was determined relative to that average.

We’re not going to go into great detail about the curves thrown by all of the pitchers listed above, but let’s do so with those who earned grades of B+ and above.

Grade A – Corey Kluber, Indians
No contest, Kluber easily had the most dominant curve in the AL last season. Its whiff rate was totally off of the charts in this company, nearly three full standard deviations above league average at 27.0%. That’s almost 10% higher than the AL runner-up. It was an effective contact-management pitch as well, with an overall Adjusted Contact Score of 70.

While he allowed a fairly significant number of fly balls with the pitch, they weren’t hit very hard (65 Adjusted Contact Score). He actually smothered contact authority across all BIP types (liner and grounder Adjusted Contact Scores of 63 and 69, respectively.)

Kluber’s curve stood out stylistically, as well. He threw the second-hardest curve among AL qualifiers (average of 83.4 mph), and it had a more slider-esque look in terms of average horizontal (9.9 inches, most among AL qualifiers) and vertical (0.3 inches) movement. All six of the pitchers we’ll discuss today had an above-average curveball spin rate; Kluber’s was the fourth highest of those six.

FanGraphs’ pitch values are in complete agreement with my analysis; Kluber’s curve ranked first in overall value and first in value per 100 pitches among AL qualifiers.

Grade B+ – Rick Porcello, Red Sox
There were plenty of reasons for Porcello’s breakthrough Cy Young campaign in 2016, but his curveball’s role has largely flown under the radar. Its whiff rate was quite low, just over a full STD below the AL average, but its contact-management value was quite significant (53 Adjusted Contact Score). While his grounder rate on the pitch was fairly ordinary, he totally thwarted grounder authority (45 Adjusted Contact Score).

There are two basic curve types on this list: the traditional, slower type thrown by Porcello (73.7 mph, eighth slowest among AL qualifiers) and three others, and the harder version by Kluber and one other pitcher. Porcello’s is actually kind of a hybrid, with the significant vertical movement (8.1 inches, fourth most among AL qualifiers) of the former group and above-average horizontal movement (9.0 inches, third most) of the latter. His average spin rate was a bit higher than Kluber’s, third highest among the six pitchers discussed today, and well above average overall.

FanGraphs’ valuation of Porcello’s curve lags well behind this analysis. It ranks 16th in overall value, and 15th in value per 100 pitches.

Grade B+ – Justin Verlander, Tigers
While Verlander has evolved in many way as a pitcher over the years, his curveball has been along for the entire ride. Though it’s stylistically quite different, the results derived on Verlander’s curve were much akin to Porcello’s: well above-average contact management (62 Adjusted Contact Score) coupled with a subpar whiff rate (7.9%).

Verlander is one of only three pitchers on the above list to throw his curve over one-quarter of the time last season. He totally shut down fly-ball authority with the pitch (39 Adjusted Contact Score).

He threw his curve harder than average (78.7 mph, seventh highest among AL qualifiers), and the shape of the pitch was quite typical (5.9 inches of horizontal and 6.3 inches of vertical movement, both squarely in the average range).

FanGraphs’ pitch values are in lockstep with this analysis: the pitch ranked third in overall value and fourth in value per 100 pitches among qualifying starters’ curves.

Grade B+ – Ricky Nolasco, Angels
This one might surprise you a little bit. Nolasco is one of four pitchers being discussed today who didn’t miss bats with his curve at a league-average rate, but he more than compensated with exceptional contact management.

Nolasco, like Verlander, significantly held down fly-ball authority (32 Adjusted Contact Score), and did nearly as well with grounder authority (49).

Like most of the curves on this list, Nolasco’s had above-average horizontal (8.8 inches, fourth among AL qualifiers) and vertical (7.5 inches, eighth most) movement. His average curveball spin rate was only fifth highest among the six pitchers discussed today, but was still well above AL average.

FanGraphs’ pitch values are not in agreement with this analysis. Nolasco’s curve ranked 13th in overall value and in value per 100 pitches. A big reason for this? Bad luck. Nolasco’s Unadjusted Fly Ball (115) and Grounder (97) were way higher than his aforementioned adjusted marks.

Grade B+ – Mike Fiers, Astros
Another potential surprise here. Fiers is the last of four low-whiff, strong contact managers. He got it done a little differently than the other pitches being discussed. Fiers’ curve induces many more grounders than his A/B+ peers. Those grounders weren’t hit very hard (69 Adjusted Contact Score), either. The few fly balls he did allow weren’t struck very well (22 Adjusted Contact Score).

Fiers’ curve was not thrown very hard (average of 73.9 mph, ninth slowest among AL qualifiers), though its overall movement was above average (6.7 inches of horizontal movement, ninth most, and 11.3 inches of vertical movement, ranking first). His average spin rate was very high, second highest among this high-spin group of six.

Here lies another significant disagreement between FanGraphs’ pitch values and this analysis. Fiers’ curve ranked 19th in overall FanGraphs value, and 17th in value per 100 pitches.

Grade B+ – Collin McHugh, Astros
Early in the Astro rebuild, McHugh was a buy-low target because of his high curveball spin rate, which remains the highest among this high-spin group. His overall pitch-specific Adjusted Contact Score was within the average range, but his 17.6% whiff rate was second only to Kluber’s.

McHugh didn’t throw his curve hard (72.4 mph, fifth slowest among AL qualifiers), though its movement was above average (its average 9.7 inches of horizontal movement was second most, its 7.6 inches of vertical movement seventh most). He threw his curve more than any other qualifying AL pitcher last season (29.9%).

He was exceedingly unlucky with his curve last season, leading to yet another disagreement with the FanGraphs pitch values. His fly-ball (115 Unadjusted vs. 49 Adjusted), liner (136 vs. 79) and grounder (70 vs. 56) Contact Scores were all out of whack, causing him to rank 12th overall and per 100 pitches in FanGraphs value. Hopefully, he’ll be back on the mound soon.

We hoped you liked reading Grading the Pitches: 2016 AL Starters’ Curveballs by Tony Blengino!

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I wonder where Lance McCullers’ curveball sits if he had qualified

Matthew Tobin

I think you meant Rich Hill


Considering that they’re talking about AL starters and Rich Hill was with the Dodgers for a fair bit of 2016 and all of 2017, I think LMJ is the one I want to know more about on this article :)