Believe or make-believe on starting pitcher strikeout numbers

Cleveland Indians starting pitcher Carlos Carrasco is dominating in everything aside from strikeouts, but that should change soon. (AP Photo/Tony Dejak)
Cleveland Indians starting pitcher Carlos Carrasco is dominating in everything aside from strikeouts, but that should change soon. (AP Photo/Tony Dejak)

Swinging strikes have a correlation with strikeouts of about .84 for starting pitchers, as good as you could expect. And we’re at the point of the season where these rates are stable for most starting pitchers, meaning they are at least half skill. So let’s use it to predict some strikeout futures.

I’m looking at percentage of swings that miss. The big-league average is 25.5%. First let’s examine the pitchers who have more swing and miss in their game than their rate of Ks (K/9) indicate.

Carlos Carrasco is dominating in everything but strikeouts, averaging just 6.83 per nine inning. His career rate is 8.87 But he’s getting 27% swings that miss — higher than his career rate of 26.1%. This data screams that the Ks will bounce back for Carrasco. Yes, his K rate historically is higher than his swinging strikes suggests but Carrasco has a proven ability to defy this; remember you get Ks looking, too.

Zack Godley is worrying owners that his rate of more than a K per inning last year was a fluke. This year, he’s barely contributing in Ks. But the swings that miss are 30.5%, largely indistinguishable from his 31.5% last year.

Aaron Sanchez tends to underperform his stuff and this year is no different. His Ks are way down especially as a percentage of batters faced given his putrid walk total of 11 in just 19.2 innings. But the percentage of swings that miss is an all-time high for him at 27% (career rate is 19.9%). Trading Sanchez because he’s hurting you in Ks is bad process but there are very reasonable reasons to trade Sanchez if you have someone in your league that loves him — and there are many who do.

We cover Patrick Corbin a lot here and he leads the league at 41% swings that miss. So his Ks thus far are no fluke.

Other guys you can believe in for Ks in the early going based on this more foundational statistic include Gerrit Cole (34.4%), Joey Lucchesi (32.0%), Zack Greinke (31.3%), Blake Snell (34.3%) and Lance McCullers (35.8%).

But swing and miss numbers do not support the elevated strikeout totals of Mike Foltynewicz (23.4%), Tyler Chatwood (23.6%) and Carlos Martinez (25.4%). Is it possible the Ks are more predictive of future Ks than the swinging strike percentage? Of course.

Now for some guys earning their depressed Ks.

I know Michael Fulmer is a fireballer and Justin Verlander had a low K rate early in his career that made zero sense. So I understood the Fulmer love this spring to a point. But it’s still not happening — his percentage of swings that miss is far below the league average at just 15%.

Aaron Nola is a fantasy darling but as a prospect was not expected to be a big swing and miss guy. He defied that last year with solid strikeouts but this year those numbers are down as are the swings that miss — 15.9% compared with 26.6% last year. Nola has faced 90 batters. So this should be stable. If it’s only half skill, split the difference and expect 21% swings that miss for the balance of the year. It’s going to be very difficult for Nola to strikeout out more than eight per nine with a number like that, never mind the 9.86 he had last year.

Why is Lucas Giolito still 44% owned? He should be released in every 12-team mixer, at a minimum. There’s little swing and miss in his game (22.1%). Let’s get his ownership below 25% so I don’t have to write about him again.

A pitcher I like who is disappointing in missing bats while excelling everywhere else is Sean Manaea (22.7%). The frustrating thing about this column is that I’m forced at times to fade players I like because the numbers say so. His FIP ERA is 4.08 (it was 4.09 last year). So if someone wants to buy closer to his 1.63 actual ERA, the model says to sell. Manaea’s career percentage of swings that miss is 25.1%.

Finally, I like Miles Mikolas’ velocity but his strikeouts are disappointing and likely to remain that way given he’s at 20.6% swings that miss. Velocity is a good indicator for stuff but movement and command obviously matter, too. Witness that Mikolas is leveraging his average 93.9 mph fastball for just 6.6 Ks/9 while Greinke, at just 88.9 mph on average with his heater, is at 11.2 K/9 with swinging strikes that back it up.

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