Starting Pitchers Are Inducing Fewer In-Zone Whiffs
A week ago, I discussed the American League starting pitchers who have improved their Z-Contact% (batter contact rate on pitches inside the strike zone) most versus 2017. Today, let’s take a look at the pitchers on the other side — those who have induced fewer in-zone whiffs, meaning their Z-Contact% marks are well above what they posted last season.
| Name | 2018 K% | 2018 Z-Contact% | 2017 Z-Contact% | Diff |
|---|---|---|---|---|
| Mike Clevinger | 17.2% | 90.8% | 80.1% | 10.7% |
| Corey Kluber | 27.4% | 89.8% | 82.4% | 7.4% |
| Sal Romano | 13.8% | 93.3% | 86.2% | 7.1% |
| Carlos Carrasco | 21.5% | 90.3% | 84.8% | 5.5% |
| Aaron Nola | 20.2% | 89.4% | 84.1% | 5.3% |
| Robbie Ray | 36.1% | 86.0% | 81.0% | 5.0% |
| Clayton Kershaw | 26.9% | 87.3% | 82.4% | 4.9% |
| Ian Kennedy | 19.1% | 88.9% | 84.0% | 4.9% |
| Zack Godley | 25.3% | 93.0% | 88.8% | 4.2% |
With a rotation spot locked up out of the gate and a big strikeout rate en route to a mini breakout in 2017, Mike Clevinger was a favorite sleeper of many. Then, he posted a sparkling 25/4 K/BB ratio during the spring, exciting owners even more. Unfortunately for owners, that strikeout ability seems to have suddenly disappeared. His pitch mix is nearly identical to last year, and if you believe the Pitch Info data, his fastball velocity is actually up. It’s his slider that’s behind the loss of in-zone whiffs, as the pitch’s Z-Contact% has spiked from a sterling 61.9% last year to a weaker 85.7% mark this season. That’s quite the jump! It’s likely last year’s rate was unsustainable and this looks like a more reasonable level to sit at. He still throws three pitches with double digit SwStk% marks, so I’d bet the strikeout rate gets back into the 20% range…though not nearly as high as last year.
You would have no idea by just looking at ERA, but did you realize that Corey Kluber has posted the highest Z-Contact% in his career, along with the lowest SwStk% since 2013. Like Clevinger, it appears Kluber is coming off an unsustainably low level, artificially increasing the gap between last year and this year’s mark. One of the most insane stats I have seen this early on is the Z-Contact% of Kluber’s sinker — 100%! Batters have literally made contact with every single Kluber slider thrown inside the zone this year. Wow. His career mark stands at 93.7%, so he was never very good at inducing swings and misses on the pitch, but this is crazy. His slider and four-seamer are also about ten percentage points above his career marks. Oh, and his velocity is down across the board, but nothing too significant to be alarmed about. At age 32, I’d be at least a little nervous given his cost.
Just a reminder that spring stats mean nothing — Sal Romano struck out 29% of the batters he faced then, and yet after five starts that actually count, he’s struck out a meager 13.8% of batters. And his SwStk% is just 5.1%! Unacceptable for a guy who can hit the high 90s with his fastball.
Man, what’s going on with Indians starters?! Carlos Carrasco is the third Cleveland hurler to find his name on this scary list. He has thrown his slider a bit more at the expense of his curve, but that should be a good swap — his slider has been his best whiff inducing pitch throughout his career. However, that pitch is what has caused his Z-Contact% issues so far this season. Its Z-Contact% has skyrocketed from 73.5% to 90.6%!
Aaron Nola has always generated his strikeouts thanks to a sky high called strike rate, as his SwStk% marks have not supported his strikeout rates. But this year, his ability to miss bats has regressed, meaning he’ll have to rely on the called strike even more to maintain a mid-20% strikeout rate. His strikeout ability is driven by his curve, but that pitch, along with his four-seamer, have induced far fewer in-zone whiffs.
Guess who’s back…the bad and ERA estimator underperformer version of Robbie Ray! Amazingly, his strikeout rate has reached a new level, despite the fact that he’s lost his skills at generating in-zone whiffs. That’s because he’s offset it with his best O-Contact%, a mark that has actually improved every single season. It didn’t hurt him last year, but that inflated Hard% is now taking its toll. Hard hit balls, along with poor control, is a bad combination.
Clayton Kershaw’s Z-Contact% is at its highest since he debuted in 2008. This one might be easier to explain than the others though — his four-seam velocity has dropped below 93 mph for the first time, averaging just 91.9 mph. He has seemed to acknowledge the velocity loss by reducing his usage of the pitch in exchange for his slider, and that should be a positive for his whiff-inducing ability. But his slider Z-Contact% has jumped above 80% for the first time in his career. Might a decline in velocity be reducing the effectiveness of his slider? Perhaps.
How I ended up rostering Ian Kennedy in two leagues, I don’t know. I literally hold my breath on every pitch, as I just naturally assume it’s going to end up in the outfield seats. If he continues failing to induce in-zone whiffs, that’s precisely what’s going to happen! His velocity and pitch mix are normal, but his normally excellent changeup has not been excellent. Interestingly, three of his four pitches have generated the same 87.5% Z-Contact%.
I was a fan of Zack Godley heading into the season, even though there was always at least one owner who was more of one than I was in my leagues. He’s seemingly picking up right where he left off last season, but his velocity is down, and no batter has missed his rarely used changeup. Like his rotation mate Ray, Godley has offset his loss of Z-Contact% by improving his O-Contact% to a career best. I wonder if this is somehow a Diamondbacks thing.
Mike Podhorzer is the founder of ProjectingX IQ, an advanced fantasy baseball analytics platform that transforms projection data and in-season performance signals into actionable intelligence. He is the 2015 Fantasy Sports Writers Association Baseball Writer of the Year and three-time Tout Wars champion. He is the author of the eBook Projecting X 2.0: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. Follow Mike on X@MikePodhorzer and contact him via email.
Half this list is NL, am I missing something?
My first thought as well.
Just my daily screwup. Nothing to see here, move along. It was supposed to be only AL, but naturally I forgot to remove the NL pitchers.
I think the easier solution would be to change the name of the article.
Mike, how many sinkers do you have kluber being hit off so far? On baseball savant it looks like he has only had 12 put in play. Obviously he is a bad fastball guy, but it could be a small sample size
Def a small sample, but was worth noting.
I wonder if there is any significant change to the environment the DBacks play in that could be having an unforeseen impact …
I’m not sure what you’re hinting at. Explain how the use of the humidor would decrease in-zone whiffs, but increase out-of-zone whiffs.
Would a pitch that breaks, but still stayed in the zone as of last year, now breaks and end up outside the zone? Same pitch being thrown, that would look the same to a swinging hitter, but it would be registered as inside/outside the zone differently.
Theoretically the humidor should make it easier for pitchers to grip the ball which should lead to better movement and MORE whiffs, not less. It’s also possible that the humidor could raise the seams a fraction which again would increase movement and mean more whiffs. However the impact of the latter should be miniscule and the former is speculation (though it would be interesting to track spin rates to see). In the absence of some empirical data, humidor doesn’t make any sense here.
The biggest impact of the humidor is softer, “soggier” baseballs that won’t fly as far when hit because the ball has a lower COR.
Three of the top four on this list are Cleveland’s top three pitchers – it certainly does beg the question “what’s going on with Indians starters?” On another note, are K rates up or down so far this year compared to this time last year for veteran players?
Mike – my question would be whether there is an April effect for Z-contact% since you are comparing April numbers to season-long #s. IOW, do all pitchers have higher contact rates in April?
I just looked at Kluber and it looks to me like his z-contact has definitely gone down from April to mid-season in a couple years but then other years it’s kind of flat.
Unfortunately, Z-Contact% and all plate discipline metrics aren’t available on any of the splits leaderboards, so I can’t look at leaguewide trends.
But strikeout rate does rise as the year progresses, since velocity increases, so it would follow that Z-Contact% drops.
Plate Discipline split by handedness would be *really* helpful in figuring out whether hitters are improving against same-side pitchers (or in the case of switch hitters, weaker hitting side).
I posted this elsewhere, but this comment section is more active so here goes:
Can I ask what would seem to be a really dumb question?
Where does one find Batted Ball stats (SwStr%, e.g.) filtered by pitch type? I’ve tried to dig deep both on the player pages here and at Brooks Baseball and can’t seem to find it.
Thanks for what I’m sure is an obvious answer.
Click on Splits and then Pitch Type Splits. Scroll to the bottom and it gives plate discipline metrics.
Thanks Mike!
Three Indians? They had some really really terrible and cold weather for a long stretch. I wonder if that’s why they are all on the list yet still performing well since the hitters they faced were just as cold and miserable as them.