Monday, July 18, 2011

Alburquerque Nearly Un-hittable

It is well documented that Tigers reliever Al Alburquerque is striking out batters at an incredible clip.  With 47 strikeouts in 29 2/3 innings, he leads the American League with 14.3 strikeouts per nine innings.  If he keeps up that pace, he will have one of the top ten strikeout rates in the history of baseball.

His 2.74 ERA is a little less impressive, but we know that ERA is not a good statistic for relief pitchers.  One reason is because relievers often enter games with runners on base and give up another pitcher's runs.  Conversely, they may leave games with runners on base and get charged for runs that scored due to hits allowed by other relievers.

One alternative to ERA is the Fielding Independent Pitching (FIP) statistic.  FIP  estimates what a pitcher's ERA should be based on fielding independent statistics - walks, hit batsmen, strikeouts and home runs.  FIP is independent of fielders and also the performance of other relievers.  Alburquerque currently has a very low 2.22 FIP because of his astronomical strikeout rate and because he has yet to allow a homer.

Weighted Component ERA (WERC) is another ERA estimator which adds hits to everything that FIP includes.  Thus, it estimates what a pitcher's ERA should be based on walks, hit batsmen, strikeouts, home runs and hits.  Why might WERC be useful for relief pitchers?  There is growing evidence that relievers (especially very good ones) have more control over the results of batted balls than starters.  The phenomenon has been studied by Lewie Pollis of Wahoo Blues and Dave Studenmund at The Hardball Times among others.  It has been found that at least some relievers tend to allow fewer hits on batted balls throughout their careers than most starters.

One theory is that relievers only have to pitch to a few batters per game and can throw their best stuff on every pitch, whereas starters need to pace themselves throughout the game.  Therefore, relievers may be able to induce weaker contact than starters.  With this in mind, it might make sense to include hits in the evaluation of relievers even if it has been shown that most starters have limited control over batted balls.  Thus, WERC might be a good alternative to FIP in evaluating relievers.


Because he has allowed just 4.6 hits per nine innings to go with his large number of strikeouts and zero homers, Alburquerque's WERC is even lower than his FIP.  In fact, he leads the American League with a 1.66 WERC.  The AL league leaders with 25 or more appearances in 2011 are listed in the table below. 

Table 1: AL Reliever WERC Leaders as of July 17, 2011


Player
Team
G
IP
Base Runs/9 IP
WERC
Al Alburquerque
DET
28
29.2
1.79
1.66
Scott Downs*
LAA
35
31.0
1.81
1.69
David Pauley
SEA
35
48.1
1.94
1.81
Daniel Bard
BOS
44
46.1
2.02
1.88
Koji Uehara
BAL
40
44.0
2.19
2.04
Jesse Crain
CHW
41
41.2
2.32
2.16
Glen Perkins*
MIN
37
35.2
2.38
2.22
Mariano Rivera
NYY
37
35.0
2.43
2.26
Kyle Farnsworth
TBR
41
38.0
2.44
2.26
Joe Smith
CLE
37
34.2
2.47
2.30
Grant Balfour
OAK
37
36.2
2.51
2.34
David Robertson
NYY
39
36.1
2.55
2.37
Vinnie Pestano
CLE
39
35.1
2.70
2.51
Marc Rzepczynski*
TOR
41
37.0
2.72
2.53
Chris Perez
CLE
37
34.1
2.74
2.55
Juan Cruz
TBR
38
34.0
2.74
2.55
Brandon League
SEA
40
37.2
2.75
2.56
Matt Albers
BOS
31
38.0
2.77
2.58
Sergio Santos
CHW
36
42.0
2.82
2.63
Jordan Walden
LAA
40
39.0
2.88
2.68


Other Tiger relievers are listed in Table 2 below.  Set-up man Joaquin Benoit (3.48) and closer Jose Valverde (3.51) trail the Amazing Al by a wide margin.  Now, one thing that WERC does not do is take into account the game situation in which relievers pitch, but that's a topic for another post.  For now, I'll just say that Alburquerque has been close to un-hittable when he has pitched.

Table 2: Tigers Reliever WERC Leaders as of July 17, 2011


Player
G
IP
Base Runs/9 IP
WERC
Al Alburquerque
28
29.2
1.79
1.66
Joaquin Benoit
40
35.0
3.74
3.48
Jose Valverde
44
41.2
3.77
3.51
Daniel Schlereth*
29
25.2
5.57
5.18
Ryan Perry
20
22.1
5.64
5.25

The raw data used to create the statistics in this post was extracted from Baseball-Reference.

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