Sunday, June 10, 2007

Run Preventing Events Update

Today, I’ll return to the batted balls versus pitchers theme of last winter. To review, an at bat can result in any of the following events:


  • Strikeout
  • Base on balls
  • Hits batsman
  • Ground ball
  • Line drive
  • Outfield fly
  • Infield fly

Three of those events are generally favorable events for pitchers:


  • Strikeout (SO)
  • Ground ball (GB)
  • Infield fly (IFF)

I will call these run preventing events (RPE). Of course, a ground ball is not as easy an out as a strikeout or an infield fly and can have a negative result for a pitcher. However, inducing a lot of ground balls will help to prevent runs over the course of a season. On the other hand, it is good for pitchers to avoid, for the most part, the following events:


  • Base on balls
  • Hits batsman
  • Line drive
  • Outfield fly

Last year, I constructed a stat called Run Preventing Event Percentage (RPE%) = (SO + GB + IFF)/BFP where where BFP = Batters Faced by Pitcher. Striking out batters and inducing grounders have been shown to be repeatable skills. Getting batters to hit infield flies is not stable from year to year (correlation = .10 between 2005 and 2006). However, infield flies are relatively rare compared to other batted ball types and including them does not change the RPE% substantially in most cases. Plus, I suspect (without statistical evidence) that this is a real ability for some power pitchers.


It turns out that RPE% is fairly stable with a .66 correlation between 2005 and 2006. It can also be considered a fielding independent stat because, although the end result is not independent of fielders, getting a grounder or infield fly to happen in the first place has nothing to do with fielders. It is as stable or more stable than FIP but it is not weighted and thus does not explain as much about runs allowed. RPE% is just an exploratory stat for now.


There are 47 American League starters with 60 or more innings pitched so far. Table 1 lists the RPE% rankings for Tigers starters. Table 2 lists the top 20 pitchers in the league. The raw dataused for the calculations were extracted from The Hardball Times database. We can see that Jeremy Bonderman (RPE%=58.5) ranks very well (7th in the AL) as he does on most fielding independent stats. As with the FIP stat discussed yesterday, Justin Verlander does not rank especially well on this statistic: 24th at 53.2%. Because he is good at stranding base runners, I suspect his RPE% with runners on base is better. Still, I believe he will need to improve his FIP components (more ground balls, more strikeouts or fewer walks) in order to keep his ERA down. Nate Robertson (25th) and Chad Durbin (30th) rank a little better on this statistic than they did on FIP.

Table 1: Run Preventing Events for Tigers Starters through June 9, 2007

Rank

Pitcher

BFP

K

GB

IFB

RPE

RPE%

7

Bonderman

299

64

103

9

176

58.8

24

Verlander

319

56

102

12

170

53.3

25

Robertson

296

34

119

5

158

53.2

30

Durbin

296

36

109

10

155

52.4

45

Maroth

294

22

98

9

129

44.0



Table 2: Run Preventing Events for Top 20 AL Starters through June 9, 2007

Pitcher

Tm

BFP

K

GB

IFB

RPE

RPE%

Carmona

CLE

307

33

163

2

198

64.6

Beckett

BOS

285

67

104

11

182

63.7

Wang

NYA

256

29

127

5

161

62.8

Burnett

TOR

360

96

117

8

221

61.3

Halladay

TOR

280

46

121

4

171

60.9

Meche

KC

378

68

148

12

228

60.3

Bonderman

DET

299

64

103

9

176

58.8

Bedard

BAL

343

95

101

5

201

58.7

Gaudin

OAK

328

51

127

9

187

57.1

Cabrera

BAL

366

68

130

11

209

57.0

Escobar

LAA

298

52

105

12

169

56.9

Sabathia

CLE

365

83

114

9

207

56.6

Blanton

OAK

366

63

130

12

206

56.2

Pettitte

NYA

349

46

140

9

195

56.0

Shields

TB

387

83

117

15

216

55.8

Guthrie

BAL

255

42

95

4

141

55.3

Buehrle

CHA

279

48

97

8

153

54.8

Loe

TEX

283

35

118

2

155

54.8

Santana

MIN

344

96

79

11

187

54.3

Haren

OAK

374

76

108

17

201

53.7

4 comments:

  1. The fact that Carmona tops this list, despite only striking out 33 batters, is astounding. Is there reason (I hope) to think the groundball rate will regress toward the mean?

    ReplyDelete
  2. From what I gather, he is supposed to have one of the best sinkers in the game so he may be able to keep it up. The data is limited but he had a GB rate close to 60% last year as well. Of course, this kind of pitcher needs a good infield defense behind him. The good news for us is that the Indians don't have that so he might start giving up a ton of hits like he did last year.

    ReplyDelete
  3. Lee,

    What do you make of Verlander's RPE and FIP numbers?

    These stats seem to indicate that Verlander is the luckiest pitcher in baseball...

    A rookie season of 17-9 with a 3.63 ERA may have been a stroke of luck, but a sophomore season of 9-2 with a 2.78 ERA, and a no-hitter, has to be proof that Verlander is doing something that these stats are missing.

    ReplyDelete
  4. Erik, Verlander has a very good LOB% meaning he strands a lot of runners. That is the main reason he is able to keep his ERA down. That is not generally a skill but it can be for some. Still, you won't find any pitchers with a lot of success year after year just based on LOB%.

    He'll need to improve his peripherals - k rate, BB rate, GB rate - if he is going to be successful every year. I believe he will. In fact, it's already happening. I haven't re-calculated his RPE but his FIP has improved a lot in his last three starts.

    ReplyDelete

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