03 March 2012

AL Central FIP and Pitching xWARs by Slot

There is a series of articles by Jack Sackman that you can find here.  It is an idea I found interesting an often use when I describe pitchers as a certain type of slot pitcher.  I think in common use a person referring to a guy as a one slot pitcher is more or less actually saying that the guy is a one slot pitcher on a first division team.  In other words, an ace on one of the ten best teams in baseball.  In this series of posts, I plan on going through each division and describing what each slot means and how that relates to teams.
AL East | Central | West
NL East | Central | West
For each team, slots were broken down in 32 starts per slot (for a total of 160 games).  Pitchers were ordered by FIP, lowest to highest.  They were then broken up into slots.  Their FIPs were weighted by inning allotment and a weighted average was calculated for each slot.

An example:
Chris Tillman had an FIP of 3.99 over 11 starts, Zach Britton had an FIP of 4.00 over 28 starts, and Jeremy Guthrie had an FIP of 4.51 over 32 starts.  For the purpose of this study, Tillman's 11 starts all counted for the Orioles slot 1 along with 21 of Britton's 28 starts.  The remaining 7 starts were put into the slot 2 position with 25 of Jeremy Guthrie's starts.  When a pitcher's starts are split between multiple slots, it is assumed that their FIP is equal for every inning thrown and that their IP are equal for every start.
AL Central


What I find exceptionally interesting here is how good the White Sox pitching was last year.  No one was Verlander-esque on the team, but the FIP of the ChiSox 5 slot (predominantly, Mark Buerhle) was right in line with the best non-Sox 3 slot.  Although the ChiSox pitching was so incredible, they finished with 79 wins due to an anemic offense.  Adam Dunn, Juan Pierre, and Alex Rios all had negative WAR and had almost 2000 plate appearances.  What a waste of a rotation.

Below is the AL Central FIP by Slot Table.

1 2 3 4 5
Indians 3.28 3.93 4.26 4.39 4.89
Royals 3.73 4.17 4.33 4.47 5.21
Tigers 2.85 3.44 4.08 4.28 5.14
Twins 3.64 4.10 4.23 4.50 4.78
White Sox 3.29 3.52 3.74 3.85 4.12


The following graph is simply a predicted fWAR value using only FIP and IP as described in this post.  It serves as an approximation of fWAR worth.

Again, what the ChiSox did last year throwing the ball was impressive.  Injuries and trading Edwin Jackson (who recorded the majority of the 1 slot outings) did little to affect the quality of the rotation.

Below is the xWAR AL Central  by Slot Table

1 2 3 4 5
Indians 4.94 2.78 2.48 1.98 0.70
Royals 3.63 2.60 2.37 1.52 -0.32
Tigers 6.33 4.39 2.72 2.20 0.02
Twins 3.87 3.08 2.27 1.51 0.93
White Sox 4.75 4.13 3.80 3.52 2.93

Comparison to Orioles
It should be informative that the Orioles' 1 slot pitching performance (2.5 xWAR) is less than the White Sox' 5 slot pitching.  The Orioles' 2 slot pitching perforamnce (2.14 xWAR) is less than the Tigers' 4 slot pitching.  The worse pitching performance (Royals, -0.32 xWAR) is a factor 12 better than the Orioles' 5 slot (-4.04 xWAR).  Not good.

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