Ground ball Pitchers

ERA has traditionally been used to evaluate overall pitching performance but it is problematic because it does not separate pitching from fielding. More and more, I've been using FIP ERA (or ERA) which is calculated using only statistics over which a pitcher has control - strikeouts, bases on balls, hits batsmen and home runs. FIP is more predictive or more stable from year to year than ERA.

In my article on repeatable pitching skills, I showed that SO/IP (correlation=.77) and BB/IP (correlation=.67) are very repeatable from one year to the next. Home runs per IP is less consistent (.38) and it is also park dependent. For this reason, many analysts are now using ground ball percentage (percent of batted balls which are hit on the ground) more than home runs. Ground ball percentage is relatively consistent (.73) and is also not very dependent on ballpark. One disadvantage of ground ball rate is that it is not an actual outcome. Getting a batter to hit a ground ball is fielding independent but getting the ground ball to turn into an out is not.

The statistic QERA, developed by Nate Silver at Baseball Prospectus, uses GB% instead of home runs:

QERA= (2.69 - SO% x .34 + BB% x 3.88 - GB% x .66)^2

While QERA is more predictive of future performance than ERA (.51 versus .33), I have not found it to be more predictive than FIP (.54). Still, GB% by itself is a useful tool which helps to describe an important pitching skill.

While a ground ball does not always produce a good result for a pitcher, it’s much less likely to produce a bad result than a line drive or a fly ball. Table 1 (data taken from a discussion at Fangraphs) shows that ground balls result in a much lower slugging average than either line drives or fly balls.

Table 1: Slugging Percentage By Batted Ball Type

Event	SLG
Line drive	.978
Ground ball	.220
Fly ball	.494

Futhermore, Table 2 (taken from The Hardball Times Baseball Annual 2007) indicates that a ground ball is less likely to contribute to runs than either a fly ball or a line drive. The exception would be an infield fly but those are much less common than outfield flies. Whatever way you look at it, it is clear that the ability to get batters to hit the ball on the ground is a good thing.

Table 2: Run Impact of Batted Ball Type

Event	Run Impact
Line Drive	.391
HBP	.355
Walk	.355
Outfield Fly	.192
Intentional Walk	.075
Ground ball	.045
Bunt	.021
Infield fly	-.088
Strike out	-.113

Table 3 shows how Tigers pitchers ranked in 2006 in ground ball percentage. Table 4 lists the top 20 ground ball pitchers in the American League in 2006. Kenny Rogers (50%), Jeremy Bonderman (48%) and Nate Robertson (47%) were in the top 12 among 56 American League pitchers with 17 or more starts in 2006. Justin Verlander (42%), on the other hand had a below average ground ball rate. Zach Miner (47%), the next most frequent Tigers starter, had the same ground ball rate as Robertson.

Table 3: Ground ball Rates for Tigers Starters in 2006

GB% Rank	Name	IP	GB%	ERA	FIP ERA
7	Rogers	204.0	0.50	3.84	4.81
10	Bonderman	214.0	0.48	4.08	3.41
12	Robertson	208.7	0.47	3.84	4.84
36	Verlander	186.0	0.42	3.63	4.47
---	Ledezma	60.3	0.34	3.58	4.30
---	Maroth	53.7	0.42	4.19	5.99
---	Miner	93.0	0.47	4.84	4.57

*Note: These FIP ERAs include HBP and are slightly different from those posted earlier.

Table 4: Top 20 Ground ball Rates in American League in 2006

GB% Rank	Name	Team	IP	GB%	ERA	FIP ERA
1	Wang	NYA	218.0	0.63	3.63	4.03
2	Westbrook	CLE	211.3	0.61	4.17	4.00
3	Hernandez	SEA	191.0	0.58	4.52	4.03
4	Halladay	TOR	220.0	0.57	3.19	3.72
5	Janssen	TOR	94.0	0.53	5.07	4.89
6	Burnett	TOR	135.7	0.51	3.98	3.91
7	Rogers	DET	204.0	0.50	3.84	4.81
8	Bedard	BAL	196.3	0.49	3.76	3.72
9	Loewen	BAL	112.3	0.49	5.37	4.32
10	Bonderman	DET	214.0	0.48	4.08	3.41
11	Pineiro	SEA	165.7	0.48	6.36	5.36
12	Robertson	DET	208.7	0.47	3.84	4.84
13	Fossum	TB	130.0	0.46	5.33	5.45
14	Haren	OAK	223.0	0.45	4.12	4.24
15	Beckett	BOS	204.7	0.45	5.01	5.24
16	Sabathia	CLE	192.7	0.45	3.22	3.43
17	Escobar	LAA	189.3	0.45	3.61	3.74
18	Contreras	CHA	196.0	0.45	4.27	4.22
19	Millwood	TEX	215.0	0.45	4.52	4.00
20	Redman	KC	167.0	0.44	5.71	5.11

*Note: These FIP ERAs include HBP and might be slightly different from those posted earlier.

PrOPS to the Tigers

In yesterday’s post, I presented some data on batted ball types for Tiger batters. The lists of leaders and trailers are somewhat useful for describing players but the batted ball data can also be used for evaluation and projection. There is a statistic called PrOPS (predicted OPS) developed by J.C. Bradbury at The Hardball Times which estimates what a batter’s OPS “should have been” based on strikeouts, walks, home runs and batted ball types. Bradbury discussed Props in Introducing PrOPS, an article he wrote last year.

PrOPS helps to identify which players may have been lucky or unlucky in a given year and hints at which ones may improve or regress in the following year. The OPS and PrOPS for Tigers batter in 2006 are given in Table 1 below. A player with an OPS exceeding his PrOPS may have been lucky (e.g.. his bloopers dropped in front of fielders or his grounders found holes). This player might be expected to have a lower OPS in 2007. A player with an OPS falling below his PrOPS may have been unlucky (e.g. their line drives were hit right at opposing fielders). This batter might be expected to have a higher OPS in 2007.

The table shows us the following:

• Marcus Thames had the highest PrOPS (.894) on the team in 2006.

• Carlos Guillen had an OPS (.920) which was 82 points higher than his PrOPS (.838). This indicates that we might not expect a .920 OPS next year. He may have been a little lucky in 2006 but I don’t think he was 82 OPS points lucky so I wouldn’t expect that much of a drop.

• Sean Casey’s OPS (.650) was 136 points lower than his PrOPS (.785). This makes sense. Casey did not hit well for the Tigers but I don’t think he was as bad his .650 OPS indicated. I think we will see some improvement from him next year.

• The next biggest differential was for Omar Infante whose OPS (.740) exceeded his PrOPS (.687) by 53 points. So, if he hits the same next year, his OPS might be a little lower.

Table 1 – OPS and PrOPS for Detroit Tigers Batters in 2006

Player	PA	OPS	PrOPS	OPS-PrOPS
Thames	390	0.882	0.894	-0.012
Guillen	622	0.920	0.838	0.082
Ordonez	646	0.827	0.808	0.019
Monroe	585	0.783	0.806	-0.022
Casey	196	0.650	0.785	-0.136
Inge	601	0.776	0.784	-0.008
Shelton	412	0.806	0.782	0.024
Granderson	679	0.773	0.767	0.005
Rodriguez	580	0.769	0.743	0.025
Polanco	495	0.693	0.727	-0.034
Infante	245	0.740	0.687	0.053

Grounders, Liners and Fly Balls

A lot of times you hear people talk about how their favorite player does not have good stats but he's been hitting the ball hard and has just been unlucky. For years, there was no way to measure how well players were hitting the ball and all we could do was go by memory. Now, with more advanced play by play data collected by companies like Baseball Info Solutions, it has become possible to to answer questions about the frequency of line drives, ground balls or fly balls players are hitting.

This data has been aggregated and made available year round by The Hardball Times (THBT) site. The data are also summarized in tables and essays in The Hardball Times Annual. As an introduction to batted ball data, I am presenting data from THBT for the Tigers in the tables below. To give the Tigers data some context, Table 1 lists the average rates of frequency for differnt batting events in the American League in 2006. Table 2 lists the average rates for batted ball types.

The first table shows that one out of four plate appearances in 2006 resulted in a walk, a strike outs or a hits batsmen. The other three quarters of plate appearances yielded batted balls which turned into hits or outs. We can see in the second table that the most common batted ball type of all balls put in play was a ground ball (44%). Fly balls (36%) and line drives (20%) happened less frequently.

Table 1: AL Averages for Batting Events Per Plate Appearance

BB/PA 8%
K/PA 16%
HBP/PA 1%
BIP/PA 75%

Table 2: AL Averages for Batted ball Types Per Balls in Play

GB% 44%
FB% 36%
LO% 20%

Tables 3-12 list the Tigers leaders and trailers for each batting event. So what does this all mean? Which Tigers were lucky or unlucky? For today, I'll let you draw your own conclusions. I'll give you the answers (or at least the theoretical answers) in my next post.

Table 3: Highest K/PA for Tigers

Chris Shelton 26%
Curtis Granderson 26%
Marcus Thames 24%

Table 4: Lowest K/PA for Tigers

Placido Polanco 5%
Sean Casey 11%
Magglio Ordonez 13%

Table 5: Highest BB/PA for Tigers

Carlos Guillen 12%
Marcus Thames 11%
Curtis Granderson 10%


Table 6: Lowest BB/PA for Tigers

Placido Polanco 5%
Ivan Rodriguez 5%
Craig Monroe 6%


Table 7: Highest GB% for Tigers

Placido Polanco 51%
Ivan Rodriguez 50%
Magglio Ordonez 45%


Table 8: Lowest GB% for Tigers

Marcus Thames 26%
Chris Shelton 33%
Craig Monroe 38%

Table 9: Highest FB% for Tigers

Marcus Thames 59%
Chris Shelton 48%
Brandon Inge 46%

Table 10: Lowest FB% for Tigers

Placido Polanco 28%
Ivan Rodriguez 28%
Sean Casey 34%

Table 11: Highest LD% for Tigers

Sean Casey 23%
Curtis Granderson 22%
Ivan Rodriguez 21%

Table 12: Lowest LD% for Tigers

Brandon Inge 14% (lowest in league)
Marcus Thames 15%
Magglio Ordonez 18%

Bonderman Signed Through 2010

The Detroit Tigers and Jeremy Bonderman have agreed on 4 year contract which will keep the pitcher on the Tigers through 2010. According to the Cutoff Man at MLive, WDFN radio is reporting that the deal will be worth 38 million over the length of the contract.

Bonderman would have been a free agent after 2008 but this deal buys out his last 2 years of arbitration and goes 2 years beyond that. This looks like an excellent deal for the Tigers. As Billfer points out, this is very similar to the deal received by Johan Santana last year in a more conservative market.

This is a very important signing for the Tigers. Bonderman gets a lot of criticism from fans but people forget that he was just 23 years old last year and has been improving each year. Bonderman was 14th in the league with a 4.08 ERA and had an excellent K/BB ratio of 202/64 in 214 innings in 2006. He was 4th in the league with a FIP ERA of 3.37, 2nd in strikeouts per 9 IP (8.6), 6th in fewest homeruns per 9 IP pitched (0.77) and 7th in ground ball percentage (48.2%). So, he's already good and could become dominant as he matures.

Tiger Tales Redesign

As you can see, I am in the process of redesigning Tiger Tales. Switching from two columns to three columns allows me to move my archive and links closer to the top of the page instead of buried beneath my advertisements. The other change is that main posting column is now wider which allows me more space for my statistical tables.

There was one one glitch in my transition to the new design. That is, the format of many of my posts did not come out quite right which means I have to go back and fix them manually. Everything is still readable. The main problem is that many of the posts do not have spacing between paragraphs. Since I have over 300 posts, this will take a little time to fix but I should get all of them fixed over the next couple of weeks.

If there is anything else, you think I should do to make my blog more readable or attractive, please let me know.