Five Starters Overachieving in Strikeouts

This kind of post is right in Mike Podhorzer’s wheelhouse. We have a lot of common interests as far as baseball research topics are concerned — namely, xK%, xBB% and xBABIP — but he’s typically the one who periodically updates RotoGraphs with x-leaders and x-laggards.

So, again, this would be the kind of post Pod would tackle: an update on which starting pitchers will likely regress in their strikeout rates (xK%). But instead of using the xK% equation, to which the above paragraph is hyperlinked, I want to focus on a particular metric: zone contact rate, or Z-Contact%.

I’ll be up front about this: I haven’t done much research regarding pitcher zone contact rates and how it sticks from year to year. That’s primarily what this post will entail, and my evidence is largely anecdotal. But it’s important to note that zone contact rate plays a profound role in determining a pitcher’s strikeout rate; the Pearson correlation coefficient between K% and Z-Contact% is -0.72. In other words, K% and Z-Contact% are strongly negatively correlated.

OK, so, the anecdotal part. Take a look at the best full-season zone contact rates dating back to 2002.

  • Johan Santana leads the pack at 74.3% (2004). He repeated this mark in 2004, but the other eight seasons he pitched after 2002 clocked in above 79%, and his career rate is 81.2%. In that season, he finished the season with a strikeout rate about 4 percentage points higher than usual.
  • Matt Clement is also near the top of that list, at 76.2% (2004). We could be entering measurement error territory here, given both marks were recorded in 2004, but Clement’s Z-Contact% in his other four seasons on record ended up well above 83%. It wasn’t his best single-season strikeout rate, but it was about 5 percentage points better than his career mark.
  • Oliver Perez’s 77.5% mark in 2004 makes for yet another elite rate from that year. Perez’s next best mark occurred in 2002, at 81.0%; his career rate settled at 84.7%. Perez’s strikeout rate jumped more than 5 percentage points from 2003 to 2004 and clocked in more than 6 percentage points better than his career rate.

It seems that almost any pitcher can benefit from an anomalous zone contact rate, meaning almost any pitcher can benefit from an anomalous strikeout rate. Moreover, it seems that the best zone contact rates are typically reserved for the best pitchers in a given era. Pedro Martinez, Jason Schmidt, Randy Johnson, Clayton Kershaw, Max Scherzer, Chris Sale. These names occupy many of the remaining top spots on the leaderboard, and they show up several times. It’s no coincidence that the game’s historically great pitchers are the best at missing bats on pitches in the zone, where hitters can most adeptly make contact with the ball.

Thus, when predicting which way a pitcher’s strikeout rate might trend, one should compare a pitcher’s Z-Contact% only to that pitcher’s previous Z-Contact% marks. Not all pitchers are created equal, and while comparing Z-Contact% between pitchers illuminate who is probably more talented, comparing a pitcher to himself tells you what might be awry with him.

All of this brings me to 2016. Some wacky things have happened this season, and some interesting storylines have emerged. Matt Moore looks like he’s finally, finally, for real. Same with Drew Smyly. Hector Santiago and Rick Porcello have experienced nice breakouts of their own, too. And Jeremy Hellickson looks vaguely like the former Rookie of the Year he once was.

I’m sure you can guess the shared thread here: all five have abnormally low zone contact rates right now. Again, that doesn’t mean the gains aren’t legitimate — perhaps he made a mechanical adjustment, or he added a new pitch, or he found some untapped velocity. These things happen, and they’re the kinds of things that turn nobodies into somebodies into aces. That’s why it’s important to look for evidence of change that corresponds with the change itself.

Drew Smyly Z-Contact%
Season(s) Z-Contact% K%
2016, thru 4/24 78.60% 34.20%
2013-15 86.70% 24.30%
Career 86.40% 24.40%

Smyly’s velocity is up in his first few starts, and he appear to be throwing change-ups a bit more. But the change-ups haven’t been particularly effective, and, at only 37 pitches, the sample is likely too small to draw any meaningful conclusions. The change-up could be playing up his other pitches but, again, it might be too soon to tell. His cutter is humiliating hitters, but the 90.9 Z-Contact% suggests it’s not the culprit.

No, it’s Smyly’s four-seamer that’s fueling his success — which is kind of strange, given it didn’t really do that before. The pitch is moving quite a bit, but it, too, hasn’t been particular effective. I think the sample is still a bit too small and, unsurprisingly, I’m not sold on the gains. Ride the hot hand, but I don’t know if this is the breakout we’ve been waiting for.

(I wouldn’t be surprised if I offered this same advice for the next four names as well.)

Jeremy Hellickson Z-Contact%
Season(s) Z-Contact% K%
2016, thru 4/24 75.70% 23.80%
2013-15 85.20% 18.70%
Career 84.50% 17.80%

Depending on whom you ask, Hellickson pretty much just started using a cutter (Baseball Info Solutions), or he is relying more on his two-seamer and just started throwing a slider (PITCHf/x). Neither is very helpful, given the vast measurement disparities here.

Hellickson’s change-up has been filthy this year, but nothing about it, from its movement to its velocity, screams real change. It’s his bread-and-butter pitch, but it’s not his bread-and-butter-and-the-salad-bar-too pitch. At least Smyly was more effective on pitches outside the zone; Hellickson doesn’t really have anything going for him in that regard. I’m even less sold on him than Smyly, but anyone who has paid any attention to Hellickson’s career would likely come to the same conclusion without the evidence.

Hector Santiago Z-Contact%
Season(s) Z-Contact% K%
2016, thru 4/24 80.40% 25.70%
2013-15 85.70% 20.60%
Career 85.50% 21.40%

Santiago’s velocity hasn’t cracked 92 mph, let alone 91 mph, on average since his days as a White Sock in 2012. Yet here’s Quintana, pumping 93 like he’s a young’un. He’s not inducing more swings on pitches outside the zone, but he is forcing more whiffs on chased pitches. That has nothing to do with pitches in the zone, I know, but it would help his cause if he’s universally more effective.

The change-up looks good. It does. More movement, more velocity. But it’s not a huge margin. And, frankly, I’m not Eno Sarris or Jeff Sullivan. I’m not a pitch specialist, and I don’t know how this pans out. With my limited knowledge, color me skeptical, again.

Matt Moore Z-Contact%
Season(s) Z-Contact% K%
2016, thru 4/24 80.50% 25.20%
2013-15 87.90% 16.20%
Career 83.50% 22.00%

All of Moore’s secondary pitches have propelled Moore to a quick start. His new knuckle curve is flatter and faster than last year. Frankly, maybe it’s the pitch he has always been looking for. He has only thrown 87, so let’s be patient on this one, but Moore has actually piqued my curiosity. The next step will be waiting to see if his suppressed walk rate (BB%) is legit; I’m a lot less hopeful in that regard.

Rick Porcello Z-Contact%
Season(s) Z-Contact% K%
2016, thru 4/24 81.90% 30.80%
2013-15 88.60% 18.20%
Career 89.60% 15.40%

This is, by far, the weirdest case of the five. Porcello’s chase rate is waaaaaay down, and his overall contact rate is only a couple of percentage points lower than usual. In fact, his swinging strike rate (SwStr%) isn’t even the best of his career. Frankly, this is all just bizarre. This isn’t even a Z-Contact% thing anymore.

According to Baseball Reference, 10 of Porcello’s 24 K’s are backwards. That’s a lot of looking strikeouts — tied for 4th-most in baseball. You know what’s funny about the names above Porcello’s? Almost all of them — Jaime Garcia, Tanner Roark, Juan Nicasio, Aaron Sanchez — recently twirled gems with uncharacteristically high strikeout tallies, and none of them had really demonstrated that kind of efficacy prior or since. Coincidence? Perhaps, but it is certainly suspicious.

Anyway, maybe Porcello is doing something that utterly devastates hitters, causing them to not swing. I don’t know if that’s the kind of thing I’d want to rely on as a pitcher. Swinging strike rates correlate strongly with strikeouts, so those looking K’s might not be the most sustainable bunch.





Currently investigating the relationship between pitcher effectiveness and beard density. Two-time FSWA award winner, including 2018 Baseball Writer of the Year, and 8-time award finalist. Featured in Lindy's magazine (2018, 2019), Rotowire magazine (2021), and Baseball Prospectus (2022). Tout Wars competitor. Biased toward a nicely rolled baseball pant.

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Daniel
6 years ago

Johan Santa? Shame he didn’t stick around.