Last year I posted the Starting Pitching Rotation Slot Definitions for the 2004 and 2005 seasons. The methodology and data for the 2006 season follows.

I first extracted all starting pitching statistics. I then sorted the data for all pitchers in each league by ERA (Then later XERA). Then, for each league, beginning at the top of the list, I totalled up enough IP to account for a #1 SP for each team in the league. I totalled the statistics for these pitchers and divided by the number of teams in the league to come up with the average #1 SP for the league. I then repeated this process with the remaining pitchers for each of the remaining pitching rotation slots #2 – #5. I determined the number of innings pitched for each rotation slot, by trying to come as close to the following as I could.

Slot IP
#1 220
#2 210
#3 200
#4 190
#5 The Rest

Click below to see the data for the 2006 season.

Here is the data for the 2006 season.

2006 ERA Rotation Slots

AL Rot Slots  W  L  ERA GS  IP   H   R  ER HR BB  SO WHIP XERA
Avg AL #1 SP 17 10 3.41 35 222 209  93  84 22 63 167 1.23 3.59
Avg AL #2 SP 14 11 4.24 34 209 219 107  98 25 62 145 1.35 4.38
Avg AL #3 SP 13 11 4.65 33 199 212 110 103 24 67 142 1.40 4.52
Avg AL #4 SP 11 13 5.23 34 190 217 120 111 29 66 112 1.49 5.26
Avg AL #5 SP  6 14 6.95 29 145 198 120 112 27 58  83 1.76 6.81
Avg AL SP    12 12 4.73 32 189 206 107  99 25 62 127 1.42 4.76

Rotation Slots	ERA Range
AL #1 Starters	 Under 3.87
AL #2 Starters	3.87 - 4.44
AL #3 Starters	4.45 - 4.87
AL #4 Starters	4.88 - 5.86
AL #5 Starters	 Over 5.86


NL Rot Slots  W  L  ERA GS  IP   H   R  ER HR BB  SO WHIP XERA
Avg NL #1 SP 15  9 3.31 35 221 200  89  81 21 71 169 1.22 3.46
Avg NL #2 SP 13 12 4.07 34 209 207 104  95 24 66 161 1.30 4.05
Avg NL #3 SP 12 12 4.70 35 202 214 115 106 25 76 141 1.43 4.64
Avg NL #4 SP 10 13 5.34 34 186 211 120 111 27 70 113 1.50 5.19
Avg NL #5 SP  5 11 7.28 21 105 135  90  85 21 48  69 1.74 6.63
Avg NL SP    11 12 4.65 32 188 197 106  97 24 67 133 1.41 4.58

Rotation Slots	ERA Range
NL #1 Starters	 Under 3.79
NL #2 Starters	3.79 - 4.31
NL #3 Starters	4.32 - 4.91
NL #4 Starters	4.92 - 6.00
NL #5 Starters	 Over 6.00


2006 XERA Rotation Slots

AL Rot Slots  W  L  ERA GS  IP   H   R  ER HR BB  SO WHIP XERA
Avg AL #1 SP 17  9 3.56 36 225 208  98  89 21 64 177 1.21 3.44
Avg AL #2 SP 15 12 4.38 34 211 211 110 103 26 69 165 1.33 4.17
Avg AL #3 SP 13 12 4.56 34 200 217 110 102 26 65 127 1.41 4.67
Avg AL #4 SP 11 13 5.21 34 192 230 120 111 29 63 106 1.52 5.49
Avg AL #5 SP  6 13 6.82 28 136 189 111 103 26 55  73 1.79 7.03
Avg AL SP    12 12 4.73 32 189 206 107  99 25 62 127 1.42 4.76
																					
Rotation Slots	XERA Range
AL #1 Starters	 Under 3.94
AL #2 Starters	3.94 - 4.39
AL #3 Starters	4.40 - 5.01
AL #4 Starters	5.02 - 5.94
AL #5 Starters	 Over 5.94


NL Rot Slots  W L   ERA GS  IP   H   R  ER HR BB  SO WHIP XERA
Avg NL #1 SP 14 10 3.49 35 222 195  93  86 21 70 184 1.19 3.28
Avg NL #2 SP 13 12 4.08 34 210 206 104  95 25 67 158 1.30 4.05
Avg NL #3 SP 11 12 4.68 33 196 212 111 102 23 68 119 1.44 4.67
Avg NL #4 SP 11 13 5.25 34 188 211 119 109 28 74 121 1.52 5.23
Avg NL #5 SP  5 11 7.03 22 109 143  91  85 22 51  71 1.78 6.81
Avg NL SP    11 12 4.65 32 188 197 106  97 24 67 133 1.41 4.58

Rotation Slots	XERA Range
NL #1 Starters	 Under 3.68
NL #2 Starters	3.68 - 4.37
NL #3 Starters	4.38 - 4.95
NL #4 Starters	4.96 - 5.61
NL #5 Starters	 Over 5.61

Here is how each of the Reds starters from last season fared.

Reds SP ERA

NL #1 SP    ERA GS    IP   H   R ER HR BB  SO WHIP XERA
M Belisle  0.93  2   9.7   8   1  1  0  7   4 1.55 3.30
B Arroyo   3.29 35 240.7 222  98 88 31 64 184 1.19 3.69
S Kim      3.60  1   5.0   4   2  2  1  0   3 0.80 3.01
A Harang   3.78 35 233.3 240 109 98 28 56 215 1.27 4.09

NL #4 SP    ERA GS    IP   H   R ER HR BB  SO WHIP XERA
E Milton   5.19 26 152.7 163  94 88 29 42  90 1.34 5.00
E Ramirez  5.26 19 102.7 120  68 60 13 27  69 1.43 4.95

NL #5 SP    ERA GS    IP   H   R ER HR BB  SO WHIP XERA
C Michalak 6.15  6  26.3  37  20 18  5 13   8 1.90 7.33
B Claussen 6.19 14  77.0  93  56 53 14 28  57 1.57 5.87
J Germano  6.35  1   5.7   8   4  4  1  2   8 1.77 6.80
K Lohse	   6.19 19 100.3 123  70 69 13 38  74 1.60 5.56
D Williams 6.62 13  68.0  92  52 50 14 20  32 1.65 6.67
J Mays     9.89 10  43.7  71  54 48 11 26  21 2.22 9.23


Reds SP XERA

NL #1 SP    ERA GS    IP   H   R ER HR BB  SO WHIP XERA
S Kim      3.60  1   5.0   4   2  2  1  0   3 0.80 3.01
M Belisle  0.93  2   9.7   8   1  1  0  7   4 1.55 3.30

NL #2 SP    ERA GS    IP   H   R ER HR BB  SO WHIP XERA
B Arroyo   3.29 35 240.7 222  98 88 31 64 184 1.19 3.69
A Harang   3.78 35 233.3 240 109 98 28 56 215 1.27 4.09

NL #3 SP    ERA GS    IP   H   R ER HR BB  SO WHIP XERA
E Ramirez  5.26 19 102.7 120  68 60 13 27  69 1.43 4.95

NL #4 SP    ERA GS    IP   H   R ER HR BB  SO WHIP XERA
E Milton   5.19 26 152.7 163  94 88 29 42  90 1.34 5.00
K Lohse	   6.19 19 100.3 123  70 69 13 38  74 1.60 5.56

NL #5 SP    ERA GS    IP   H   R ER HR BB  SO WHIP XERA
B Claussen 6.19 14  77.0  93  56 53 14 28  57 1.57 5.87
D Williams 6.62 13  68.0  92  52 50 14 20  32 1.65 6.67
J Germano  6.35  1   5.7   8   4  4  1  2   8 1.77 6.80
C Michalak 6.15  6  26.3  37  20 18  5 13   8 1.90 7.33
J Mays     9.89 10  43.7  71  54 48 11 26  21 2.22 9.23

I always find these numbers interesting. I hope they help to illustrate what kind of pitcher someone is talking about when they say for instance, we really need a #3 SP for next season.