Pitch Type Linear Weights: Our Bullpen

It's time for another look into the awesome tool that is Pitch Type Linear Weights. If you missed the first part, where I introduce the stat and talk about the rotation, you can go here.

I wanted to take some time to talk about one thing that Devo noticed in a comment in my previous post. The sample size is teeny. Far too small to be all that useful. At the time of writing my last post, most of the starters I looked at had around 40 IP. Most of the relievers on the roster have pitched around half of that, which leads to an even smaller sample size. Because of this, I'll include 2008's numbers to give a larger body of work to analyze. On to the numbers!

Brad Ziegler - I'll start with our AN fan favorite (Brad, if you're reading this, hi!). PitchFX shows a fastball, that awesome frisbee slider, and a changeup.

2008

• wFB/C: 1.63
• wSL/C: 3.46
• wCH/C: 1.26

2009

• wFB/C: -0.60
• wSL/C: 5.30
• wCH/C: 1.00

That slider truly is a great pitch, baffling hitters everywhere. His fastball was very nice last year as well, considering he threw it over 85% of the time. His changeup confuses hitters pretty well too. This year, he seems to be getting less performance out of his fastball, and a lot more with his slider.  He's compensating by throwing his fastball a hair over 8% less in 2009 over 2008. I'll attribute this loss of performance on the league adjusting and realizing what a talent he is.

Andrew Bailey - Might as well continue with the good, as Bailey has shown himself to be a true gem in the bullpen. It's worth noting that he's thrown more innings than anyone else in our bullpen, as well as Dana Eveland. 34 innings in 24 games! PitchFX reports a fastball, cutter, and curveball. It also sees a slider and changeup, but those are thrown less than one percent of the time. Judging by the speed of these pitches, I'll assume they're misclassified cutters.  I'll leave them out.

2009

• wFB/C: 1.97
• wCT/C: 0.79
• wCB/C: 2.58

Thirty four career innings isn't exactly the best sample to really look at, but we can still see what Bailey's succeeded with so far. Bailey's done some pretty awesome things in his time in the big leagues, and it shows. He doesn't have a bad pitch. He throws his plus fastball sixty percent of the time, and it's working.  The occasional cutter and curveball serve as a nice change of pace, and he's succeeding with those too. Hopefully he'll be a rock in our pen for a long time.

Michael Wuertz - Another candidate in the overused department, though not nearly to the extent that Bailey has been. PitchFX shows a fastball and slider, as well as the occasional changeup. I'll throw out the extremely rare curveball classification.

2008

• wFB/C: -3.19
• wSL/C: 0.76
• wCH/C: 4.23

2009

• wFB/C: -1.02
• wSL/C: 2.74
• wCH/C: 8.41

He's never been one to dominate with his fastball, but he has a great slider he can use to get hitters out. Throwing a changeup every once in a while really catches hitters off guard. It's kind of interesting to note that he threw his fastball over half of the time in his first year, with his slider making up a quarter of his pitches. Over the years, he slowly decreased the use of his fastball and began relying more on his slider. His fastball and slider are now more like 30% and 60%, respectively.

Santiago Casilla - Casilla is kind of an odd case, as he seems to go through stretches of amazing dominance, followed by stretches of bizarre hittability. PitchFX shows a fastball, slider, and changeup. In his first three seasons, PitchFX reported about a quarter of his sliders as curveballs, which may indicate a change in the movement of his slider.

2007

• wFB/C: 0.25
• wSL/C: 1.81
• wCH/C: 0.48

2008

• wFB/C: -0.14
• wSL/C: -1.18
• wCH/C: -1.61

2009

• wFB/C: -1.83
• wSL/C: 1.68
• wCH/C: 3.30

If you go to Fangraphs, you can see the stats from all of his years, which I only bring up (and recommend) here, because Casilla is definitely an odd case. He's inconsistent. His slider and changeup numbers flip-flopped from positive to negative in 2008, only to bounce back this year. Granted, his first three years were his Jairo years, with extremely few innings pitched, but he's been inconsistent after that as well. The drop in production from 2007 to 2008 is particularly alarming. He looks like he's on the rebound from these numbers this year, but his FIP is up by two entire runs in 2009 from the low-4 FIPs he posted in 2007 and 2008. Not quite what we want to see from our once-possible future closer.

Russ Springer - Another of our somewhat unexpected free agent bullpen acquisitions. Springer's had less success this year than Wuertz, but hey, he taught Braden his cutter. Give the man his due. PitchFX shows a fastball, slider, cutter and curveball. It also reports a changeup, but I'll consider those as misclassified sliders or cutters.

His pitch type breakdown is actually quite interesting. In 2007, it looks like he cut down his slider and curveball and increased the frequency of his cutter dramatically. It seems to be that 2007 was the year he upgraded his cutter from an experiment to a pitch he used with regularity. 2008 brought the same amount of cutters, with more curveballs at the expense of his slider. This year, he's cut down on his curveballs again, increasing the frequency of his cutter yet again to 30%.

2007

• wFB/C: 1.44
• wSL/C: 3.36
• wCT/C: 3.14
• wCB/C: -1.10

2008

• wFB/C: 1.75
• wSL/C: 1.38
• wCT/C: 0.79
• wCB/C: -1.73

2009

• wFB/C: -1.54
• wSL/C: 4.64
• wCT/C: -1.60
• wCB/C: -5.63

This pitch breakdown gives us an interesting look at his linear weights. In 2007, his first year with his cutter in wide use, he dominated with it. His slider also got hitters out excellently. As he decreased the amount of sliders he threw, his cutter became less and less effective, and with that, his other pitches suffered. It would be interesting to see what would happen if he reverted to his 2007 pitch proportions.

This Fanpost is getting long enough already. In Part 3, I'll take a look at some other pitchers we have in the system. Thanks for reading, guys.