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.

SP Z-Contact% Decliners
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 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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Cole
5 years ago

Half this list is NL, am I missing something?

Jackie T.
5 years ago
Reply to  Cole

My first thought as well.

luke.shigeo
5 years ago
Reply to  Mike Podhorzer

I think the easier solution would be to change the name of the article.