Pitch Type Linear Weights: Our Rotation

Fangraphs just unveiled a new tool from the the amazing minds at Pitch Type Linear Weights. Fangraphs has an excellent introduction to how it’s calculated here if you’re interested, but all you really need to know is that it allows us to look at pitcher’s pitch types and determine which type of pitches get hit around the most, as well as each pitcher's true "out" pitch. Of course, the first thing I did was look at our green and gold.


But first, I needed some sort of frame of reference. The numbers are weighted so that zero is a perfectly average pitch, negative numbers signify below average pitches, and positive numbers are better than average. They also give two numbers per pitch. Using a fastball as an example, wFB is just a counting stat. It's how many runs above average that fastball was over the whole season. Unfortunately, it depends on how many times that pitch was thrown, and for how many innings. What's better for comparison's sake is wFB/C, which extrapolates the performance over 100 pitches. That's the stat I'll be using from here on out. To put things in perspective, Johan Santana's changeup got a 3.01 wCH/C in his 2006 Cy Young-winning season. In other words, for every 100 times Santana threw that changeup, he averaged a hair more than three runs below average saved. That's a very good pitch.

For this analysis, all the stat names are based on a two-letter code for each pitch:

  • FB = Fastball
  • SL = Slider
  • CT = Cutter
  • CB = Curveball
  • CH = Changeup
  • SF = Split-Fingered Fastball
  • KN = Knuckleball

To avoid making this Fanpost too long, I'll look at the rotation first.



Dallas Braden - Braden's an interesting case, as this year marks his first year with real consistent success. PitchFX shows him with a fastball, slider, changeup, and new for this year, a cutter. It also shows a curveball, but last year he threw it 0.3% of the time. I'm going to assume these were misclassified sliders.

  • wFB/C: -1.49
  • wSL/C: 1.44
  • wCT/C: 1.35
  • wCH/C: 2.66

Immediately, his changeup stands out. That 2.66 wCH/C is pretty great. Additionally, that mark has improved from last year's 1.96, which also isn't exactly bad, by any means. Dallas's fastball isn't doing him any favors, and he throws it 50-60% of the time. Thankfully, his excellent variety of offspeed junk helps him succeed. His improvement in his slider's performance from 2008's 0.35 to this year's 1.44 is worth noting. It also looks like his cutter is a success. Good to see.



Brett Anderson - I'll start with the rookie with more success so far. PitchFX shows a fastball, slider, curveball, and changeup.

  • wFB/C: -1.58
  • wSL/C: 0.01
  • wCB/C: 0.78
  • wCH/C: 0.66

Already, it doesn't look as good as Braden. His only above-average pitches so far are his curveball and changeup. His slider is very much average, and his fastball is a hair worse than Braden's. Obviously, as a rookie, it's understandable to not have any dynamite pitches, but on the whole, Anderson's not doing bad at all.



Trevor Cahill - Now we get into the ugly. Cahill throws a fastball, slider, curveball, and changeup, with 0.1% of pitches registering as what PitchFX calls a split-fingered fastball. I'll throw it out.

  • wFB/C: -0.96
  • wSL/C: -10.53
  • wCB/C: -5.33
  • wCH/C: 1.07

Yikes. His only above-average pitch is his changeup, and his other three pitches range from bad to atrocious. Take his slider and curveball stats with a grain of salt: he's thrown them 4.1% and 5.0% of the time, respectively, leading to a small sample size, you know the rest. No way his slider will stay ten runs below average. Still, though, it obviously hasn't been the greatest start for Trevor.



Josh Outman - Na na na na na na na na, na na na na na na na na, Out Man! Josh has a fastball, slider, curveball, and changeup.

  • wFB/C: -1.19
  • wSL/C: 5.35
  • wCB/C: -3.41
  • wCH/C: 1.84

Look at that slider! That number is probably too high to be sustainable, but still, it's a great pitch. And he's thrown it almost 20% of the time, so this isn't some absurdly small sample size fluke. I don't know what Outman did, but his slider was a full run below average last year. In fact, Josh's best pitch last year, his fastball, was still a half a run below average. That low curveball score isn't as bad as it looks: he's only thrown it 4.2% of the time this year. Additionally, this seems to confirm fears that his speedy fastball is just too straight, without much movement. He's not having very much success with it at all.



Dana Eveland - Not quite the greatest year for Dana. PitchFX shows a fastball, slider, curveball, and changeup.

  • wFB/C: -1.12
  • wSL/C: -4.83
  • wCB/C: -0.61
  • wCH/C: 1.30

This is really kind of surprising. The slider, which he throws a quarter of the time, is atrocious.  And it was his best pitch last year, at 1.76 wSL/C. Pretty much the only bright spot here is his changeup, which improved over last year by almost two runs per 100 games.



Sean Gallagher - I'm not going to show this year's stats after two games started. You don't want to see them, trust me. Gallagher throws a fastball, slider, curveball, and changeup.


  • wFB/C: -0.67
  • wSL/C: -0.72
  • wCB/C: 0.43
  • wCH/C: 0.62

Oh fine.


  • wFB/C: -0.47
  • wSL/C: 0.83
  • wCB/C: -6.78
  • wCH/C: -8.50

I'm still going to focus on last year's stats, because of Sean's mechanical issues that he's had this year. Keep in mind that these numbers were the result of 12 games with the Cubs and 11 games with the A's. Gallagher was pretty thoroughly average last year. His fastball and slider were both a tick below average, and his curveball and changeup were a bit above. With Sean's terrible 2009, we can only hope he regains last year's form and adds to it eventually.



Justin Duchscherer - Just for reference I'll look at Justin's amazing 2008 season. To, you know, make everyone else in our rotation look terrible. Or to make us all depressed. One of the two. PitchFX shows Justin with a fastball, slider, cutter, curveball, and changeup.

wFB/C: 0.74

wSL/C: 4.99

wCT/C: 2.45

wCB/C: 1.45

wCH/C: 5.82

Pretty amazing stuff, all across the board. His worst pitch, his 86-mph fastball, was still three-quarters of a run better than average! And that slider and There's simply nothing to say except that we need Duke back.



I'll take a look at the bullpen next post. Thanks for reading, guys.


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