06 March 2012

AL West 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 West


The AL West had two things last year: (1) several good pitchers and (2) home runs (which FIP uses) that are suppressed by several parks.

Below is the AL West FIP by Slot Table.

1 2 3 4 5
Angels 2.99 3.18 3.75 4.22 4.91
Athletics 2.93 3.64 4.01 4.18 4.49
Mariners 3.13 3.30 3.54 4.07 5.13
Rangers 3.24 3.50 3.71 3.99 4.54


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.

It seems my original idea about many 5 slot pitchers have negative values has not panned out as we go from division to division.  In the AL West not a single team had a negative xWAR.

Below is the xWAR AL West  by Slot Table

1 2 3 4 5
Angels 5.89 5.43 4.07 2.56 0.47
Athletics 5.75 3.98 3.05 2.55 1.59
Mariners 5.62 4.85 4.00 2.94 0.13
Rangers 5.06 4.21 3.53 3.06 1.79

Comparison to Orioles
The Orioles first and second slot pitching could work as these teams' fifth slot pitching.  This is pretty remarkable.

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