Comments on: Velocity and K/9

By: Kyle Boddy

Kyle Boddy — Tue, 15 Nov 2011 10:00:58 +0000

For whatever it’s worth, I repeated this experiment with the following constraints:

The pitcher must have been a starter
Data >= 2001 season
IP >= 500
Excludes postseason innings

I got an R^2 of 0.20 with alpha < 0.05. Seems to be a relatively valid model.

By: Breanna Bent

Breanna Bent — Mon, 10 Oct 2011 20:15:13 +0000

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By: Mike

Mike — Thu, 20 May 2010 20:54:36 +0000

Yes, this is a totally random bump on an old discussion. There are a couple guys this year who thus far are racking up some K’s despite low velocity – Mike Leake and John Ely.

By: Siddfynch

Siddfynch — Fri, 20 Feb 2009 15:40:29 +0000

wonder if the author here was confusing r-squared with the results from something like an ANOVA or GLM?

You could run FIP as the response variable in a test with things like FB velocity and predictor variables that cover different types (Fb velocity and BB:K rate would be two nicely different variables), and then assess the contribution of each to the error seen in the results. That might allow you to say that FB velocity explains 23% of variation in FIP, for example.

By: NadavT

NadavT — Wed, 18 Feb 2009 17:10:55 +0000

I think the sample size is too small to make any conclusions about the k/9 average for a particular mph class, especially at the low-speed end of the spectrum.

My point was just to argue that we would see more low-speed high-k/9 pitchers if we had more low-speed pitchers in the sample. My interpretation is that there are more high-speed pitchers in MLB, not only because of the relationship between speed and Ks, but also because high-speed pitchers are given more chances to succeed. If the trendline holds true, then you’d expect a relatively even distribution of K/9s around the line for any given speed. For pitchers with fastballs faster than 89 MPH, this is pretty much what you find — and I’d say that’s because there are enough pitchers at that level to provide a fairly representative sample. With fewer low-speed pitchers, you’re more likely to get results that look skewed, such as the apparent “ceiling” that Thor noticed above.

By: fanOFdefenseAGAIN

fanOFdefenseAGAIN — Tue, 17 Feb 2009 23:30:49 +0000

Question about an earlier selection bias argument:

Couldn’t selection bias cut the other way as well here? Don’t you expect GMs to cherry pick relatively high k/9 80-90mph pitchers and leave the rest in the minor league scrap bin?

Also, if a great fastball does allow a young prospect to “figure it out” in the majors before he is ready, wouldn’t that depress the k/9 ratio of that mph class in a systematic way? It would theoretically bring down their average, whereas the more tested, “crafty” pitcher would arrive in the big leagues at a more ideal period in his K/9 progression.

By: pappy joe

pappy joe — Tue, 17 Feb 2009 22:50:00 +0000

except Howell isn’t a LOOGY.

By: Fresh Hops

Fresh Hops — Tue, 17 Feb 2009 21:32:56 +0000

(By the way, in case it wasn’t clear, that was intended to be a sarcastic response to Brick, not to be taken seriously. Playing up the stereotype, cause how else can you respond to a very strange comment about shirts and beds?)

By: Fresh Hops

Fresh Hops — Tue, 17 Feb 2009 21:31:12 +0000

Really? What’s going on?

This is a big site for nerds. We’re total nerds over here. We don’t even know what a bed is, because we drink 2 gallons of mountain dew every day and never sleep. We just stay up all night doing regression analyses in front of our computer until April, at which point we go to sleep next until next off season, when we wake up and start doing regressions on the last season again, having used most of the built up fat from mountain due hibernating.

I can’t believer I bothered responding to this.

By: Matt Harms

Matt Harms — Tue, 17 Feb 2009 20:28:35 +0000

I think Hardball Times showed that it isn’t necessarily a great fastball, but that the biggest factor is speed differential between the fastball and the offspeed pitches. It would be cool to see the graph above, but replaced with avg speed differential on the x-axis instead of fastball speed.