FanPost

Grouping starting pitchers around the majors

So, after losing my first draft of this to a Windows crash, I'm going to be much more concise this time around. I decided to group qualifying starting pitchers into buckets 1 (ace) through 5 (bottom of the rotation) by FIP. I took all qualifying seasons by starting pitchers between 2007 and 2012 and found univariate percentiles for 20%, 40%, 60%, and 80%. This allowed me to group those observations into 5 buckets according to the following table.


p20

p40

p60

p80

FIP

3.356

3.77

4.06

4.46

So, any observation with a FIP below 3.356 falls into the first bucket (ace). Out of the remaining observations, if they have a FIP below 3.77 they fall into bucket 2, and so on. This led to the following distribution of buckets.

1

2

3

4

5

Players

87

86

86

87

88

Qualifying starting pitchers will typically be be better than the typical starters. Those who qualify are good enough to accumulate the innings necessary to meet the inning threshold to make it into the sample (assuming good and bad pitchers injured at similar rates). This will skew the results slightly as pitchers we would perceive to be better than average may be shifted down a bucket as our sample is heavy with the better pitchers. This also will have the effect of making the top buckets a bit more exclusive when we compare them to all starting pitchers in the league.

Now, let's drop the qualifying observations of starting pitchers for this season (as of games completed 7/5/2013) into the buckets we created earlier. The 93 qualifying pitchers thus far are then placed into the following buckets by team.

Team

1

2

3

4

5

- - -

0

0

1

0

0

Angels

0

1

1

1

0

Astros

0

1

0

0

1

Athletics

0

1

0

1

2

Blue Jays

0

0

0

1

1

Braves

0

2

3

0

0

Brewers

0

0

0

2

1

Cardinals

3

0

0

0

0

Cubs

1

1

1

0

0

Diamondbacks

1

0

0

2

1

Dodgers

1

1

0

0

0

Giants

0

2

1

1

0

Indians

0

1

0

0

1

Mariners

1

1

0

0

1

Marlins

1

1

1

0

0

Mets

1

0

0

2

0

Nationals

2

1

0

0

0

Orioles

0

0

0

1

2

Padres

0

1

2

0

1

Phillies

1

2

0

0

0

Pirates

1

0

1

0

0

Rangers

2

0

0

0

0

Rays

0

0

2

0

1

Red Sox

0

1

0

1

1

Reds

2

1

0

1

0

Rockies

1

1

0

0

0

Royals

0

1

1

1

1

Tigers

3

1

0

0

0

Twins

0

0

0

0

2

White Sox

1

0

1

0

1

Yankees

0

1

2

1

0

Total

22

22

17

15

17

The observation without a team is a player who has been traded. So far, it seems the qualifying pitchers this year are pitching slightly better than we would expect as 47% of the qualifying pitchers are in the 40th percentile of the previous years. I would expect some regression as we are looking at a half season worth of innings thus far.

Would anyone like to take a stab at which Phillies fall into their respective buckets so far? I imagine you guys won't be surprised by the following table.

Name

FIP

Bucket

Cliff Lee

2.67

1

Cole Hamels

3.65

2

Kyle Kendrick

3.75

2

So, their three starters who haven't been hurt are pitching great to fairly well, with Kendrick just sliding under the threshold for the 40th percentile. (Note: as I'm writing this during the game, he surely will drop one bucket.)

How are all starters across the majors doing? Well, these numbers may not mean a whole lot due to incredibly small sample sizes, but let's take a look anyway.

Team

1

2

3

4

5

- - -

0

0

1

0

1

Angels

0

3

2

1

4

Astros

0

2

0

0

5

Athletics

0

2

0

2

2

Blue Jays

0

0

1

3

7

Braves

1

2

3

0

0

Brewers

0

0

0

3

7

Cardinals

4

2

1

2

0

Cubs

1

1

2

1

1

Diamondbacks

1

1

0

4

1

Dodgers

1

1

1

3

3

Giants

0

2

1

2

2

Indians

0

2

0

1

5

Mariners

2

1

0

1

4

Marlins

3

1

0

2

3

Mets

1

0

2

2

2

Nationals

3

4

0

0

2

Orioles

1

1

0

2

8

Padres

1

2

1

1

3

Phillies

1

2

1

1

2

Pirates

4

1

2

3

1

Rangers

3

1

0

3

2

Rays

0

2

2

1

3

Red Sox

1

1

1

1

4

Reds

2

1

1

2

1

Rockies

3

1

0

0

4

Royals

0

1

1

1

3

Tigers

4

1

0

0

1

Twins

1

1

1

1

5

White Sox

1

1

1

1

3

Yankees

1

1

3

2

0

Total

40

41

28

46

89

Looking at the distribution of players across the majors, we see roughly what we would expect. The fifth bucket is extremely heavy due to the introduction of the fringe players whose performances wouldn't be represented in the original five year sample.

Let's take a look at how our Phillies starters on the whole are doing.

Name

FIP

Bucket

GS

Cliff Lee

2.67

1

18

Cole Hamels

3.65

2

18

Kyle Kendrick

3.75

2

17

John Lannan

3.78

3

7

Tyler Cloyd

4.09

4

6

Jonathan Pettibone

4.49

5

14

Roy Halladay

6.27

5

7

I included an additional column to show how small the sample sizes are both as a whole and in the cases of the players who didn't qualify for the previous table of Phillies players. Things to take from this table are that Kendrick and Lannan are hovering either side of the 40th percentile, Cloyd just missed the 60th percentile, and Pettibone just missed the 80th percentile. Don't put too much stock in those values yet, though. The season is only halfway over and these samples are still fairly small.

One last thing I looked at was how well all teams were doing as a whole. As we can see with the Phillies example, things can look drastically different when we are considering only qualifying pitchers to all starters.

Team

1

2

3

4

5

Phillies (qualifying)

1

2

0

0

0

Phillies (all)

1

2

1

1

2

A simple mean of the buckets won't tell the whole story. I chose to weight each starter by the proportion of games he started for this team to try to make it more reflective of the starts each team has gotten so far.

Team

Mean bucket qualifying

Weighted bucket qualifying

Mean bucket all

Weighted bucket all

- - -

3

3

4

3.316

Angels

3

2.980

3.6

3.465

Astros

3.5

3.541

4.143

3.931

Athletics

4

4.014

3.667

3.713

Blue Jays

4.5

4.5

4.545

4.471

Braves

2.6

2.612

2.333

2.593

Brewers

4.333

4.340

4.7

4.553

Cardinals

1

1

2.111

1.812

Cubs

2

1.961

3

2.377

Diamondbacks

3.5

3.478

3.429

3.337

Dodgers

1.5

1.486

3.667

3.106

Giants

2.75

2.768

3.571

3.141

Indians

3.5

3.417

4.125

3.756

Mariners

2.667

2.623

3.5

3.326

Marlins

2

1.936

3.111

3.047

Mets

3

2.941

3.571

3.086

Nationals

1.333

1.353

2.333

2.233

Orioles

4.667

4.694

4.25

4.488

Padres

3.25

3.239

3.375

3.310

Phillies

1.667

1.660

3.143

2.736

Pirates

2

2.097

2.636

2.576

Rangers

1

1

3

2.884

Rays

3.667

3.627

3.625

3.368

Red Sox

3.667

3.74

3.75

3.432

Reds

2

2

2.857

2.326

Rockies

1.5

1.529

3.125

3.046

Royals

3.5

3.485

4

3.759

Tigers

1.25

1.235

1.833

1.376

Twins

5

5

3.889

4.398

White Sox

3

3.082

3.571

3.349

Yankees

3

3.031

2.857

2.919

This looks similar to what we would expect as the weighted mean of qualifying starters is very close to the standard mean of qualifying starters and we can see a much larger difference between the mean across all starters and the weighted mean across all starters.

By this metric, the Phillies starters thus far have been fairly balanced, in regards to the last several years, with a weighted bucket of 2.736. A weighted bucket score of 2 would put their performance in the 20th to 40th percentile and a score of 3 would place them in the 40th to 60th. Using a crude approximation, I would estimate them to be in the range of the 35th to 55th percentiles. This was found by (bucket percentile width)*(weighted bucket all - 1) = 34.72 and (bucket percentile width)*(weighted bucket all) = 54.72. This seems reasonable based on the how close their weighted bucket is to 3. It also seems on par with their performance so far on the season.

Over the next week, I'll look to use this metric to analyze team performances at this point in the season.

X
Log In Sign Up

forgot?
Log In Sign Up

Please choose a new SB Nation username and password

As part of the new SB Nation launch, prior users will need to choose a permanent username, along with a new password.

Your username will be used to login to SB Nation going forward.

I already have a Vox Media account!

Verify Vox Media account

Please login to your Vox Media account. This account will be linked to your previously existing Eater account.

Please choose a new SB Nation username and password

As part of the new SB Nation launch, prior MT authors will need to choose a new username and password.

Your username will be used to login to SB Nation going forward.

Forgot password?

We'll email you a reset link.

If you signed up using a 3rd party account like Facebook or Twitter, please login with it instead.

Forgot password?

Try another email?

Almost done,

By becoming a registered user, you are also agreeing to our Terms and confirming that you have read our Privacy Policy.

Join The Good Phight

You must be a member of The Good Phight to participate.

We have our own Community Guidelines at The Good Phight. You should read them.

Join The Good Phight

You must be a member of The Good Phight to participate.

We have our own Community Guidelines at The Good Phight. You should read them.

Spinner.vc97ec6e

Authenticating

Great!

Choose an available username to complete sign up.

In order to provide our users with a better overall experience, we ask for more information from Facebook when using it to login so that we can learn more about our audience and provide you with the best possible experience. We do not store specific user data and the sharing of it is not required to login with Facebook.

tracking_pixel_9351_tracker