Friday, September 8
By Keith Woolner Special to ESPN.com
Editor's note: The team of writers from the Baseball Prospectus (tm) will be writing twice a week for ESPN.com. You can check out more of their work at their web site at baseballprospectus.com.
When a pitcher has an unusually poor or unusually good win/loss record compared to his ERA, we often look to his run support -- how many runs his team scored in the games he started. Often, we find that a pitcher's teammates did remarkably well or badly in the games he pitched, and we usually attribute this to luck. But do some pitchers have the deck stacked against them?
Certainly, at the beginning of the season, teams align their rotations to have their best pitchers start on Opening Day, and for a while the rotations will be in sync, with aces facing aces and so on. But as the season progresses, off days, rainouts and other factors make the matchups more randomized. Or so it's been assumed.
Are there pitchers who get unlucky in facing off against tough opposing pitchers time after time, while other pitchers get a disproportionate share of patsies? And does this relate to the amount of run support provided by his teammates over the course of a season?
To investigate this, I used a concept I call the Composite Opposing Pitcher (COP). Simply put, every time a pitcher plays a given opponent, we take the average start for that opposing starter and add it to the pitcher's composite opposing pitcher totals. Over the course of a season, the COP totals reflect the quality of opposition the pitcher faced during the year.
Let's look at a simple example. Take Jake Westbrook, who started two games for the Yankees in June. On June 17, he opposed Cal Eldred of the White Sox. On June 22, he faced off against Ramon Martinez of the Red Sox. Westbrook's COP will be comprised of the average starts for Eldred and Martinez.
Eldred had started 19 games, throwing 108 2/3 innings and allowing 60 runs, thus averaging about 5.7 innings and 3.16 runs per start. We do the same for hits allowed, walks, strikeouts and earned runs (all stats in this article are through games of September 3):
GS IP H R ER BB SO
19 108.6 101 60 56 58 93
Per Start 5.72 5.32 3.16 2.95 3.05 4.89
We repeat the process on Ramon Martinez:
GS IP H R ER BB SO
22 105.0 117 73 68 59 73
Per Start 4.77 5.32 3.32 3.09 2.68 3.32
Note that these aren't the actual totals that Eldred and Martinez posted in the games they pitched against Westbrook. In those particular games, Eldred went five innings, giving up eight hits and three runs, while Martinez threw 6 2/3 innings, allowing just two runs on four hits. Rather, what we are using is the seasonal per-start averages each pitcher posted, or what you could have expected from each pitcher on any given day.
Adding up the per start totals, we get the Composite Opposing Pitcher for Westbrook:
GS IP H R ER BB SO ERA RA
Eldred 5.72 5.32 3.16 2.95 3.05 4.89
Martinez 4.77 5.32 3.32 3.09 2.68 3.32
COP Total 10.49 10.64 6.48 6.04 5.73 8.21 5.18 5.56
Westbrook's COP had a slightly worse runs allowed average (RA) than the AL mark of 5.38, meaning that on average, he faced an easier opposing pitcher than the league standard.
Using this metric, I've rated all starting pitchers with more than 100 innings pitched (pitchers who started for more than one team have entries for each team) in increasing order by the RA of their Composite Opposing Pitcher (toughest COP appears first) for each league:
American League toughest opponents
PITCHER TEAM G ERA RA Pitcher W-L
Steve Woodard Cle 7 4.43 4.81 1- 2
Steve Trachsel TB 23 4.56 4.91 6-10
Chris Carpenter Tor 23 4.65 4.96 9-11
Mac Suzuki KC 24 4.63 5.01 8- 7
Esteban Loaiza Tor 9 4.70 5.02 8-10
Roger Clemens NYY 26 4.57 5.03 11- 6
Brad Radke Min 29 4.58 5.03 10-14
Jeff Suppan KC 28 4.64 5.05 7- 8
Albie Lopez TB 18 4.66 5.08 11- 9
Denny Neagle NYY 10 4.75 5.11 5- 4
Mike Mussina Bal 29 4.72 5.12 8-13
Bryan Rekar TB 22 4.85 5.12 5- 9
Dave Burba Cle 26 4.74 5.15 12- 6
Paul Abbott Sea 22 4.80 5.15 9- 5
Kenny Rogers Tex 29 4.83 5.16 11-13
American League easiest opponents
PITCHER TEAM G ERA RA Pitcher W-L
Jay Witasick KC 14 5.90 6.42 3- 8
Willie Blair Det 17 5.87 6.37 10- 4
Rolando Arrojo Bos 7 5.51 6.08 4- 2
Jose Mercedes Bal 14 5.48 6.07 11- 5
Jason Johnson Bal 13 5.40 5.91 1- 9
Joe Mays Min 25 5.29 5.87 6-14
Tim Hudson Oak 27 5.45 5.83 15- 6
David Cone NYY 25 5.40 5.82 4-11
John Halama Sea 25 5.34 5.82 11- 8
Andy Pettitte NYY 26 5.24 5.78 17 -7
Ramon Martinez Bos 22 5.38 5.77 9 -6
Mark Mulder Oak 25 5.30 5.70 8-10
Aaron Sele Sea 28 5.23 5.67 13-10
Pedro Martinez Bos 24 5.22 5.66 16 -4
Jeff Weaver Det 25 5.10 5.65 9-12
National League toughest opponents
PITCHER TEAM G ERA RA Pitcher W-L
Steve Woodard Mil 11 4.01 4.50 1- 7
Bruce Chen Phi 10 4.37 4.67 2- 2
Rolando Arrojo Col 19 4.22 4.68 5- 9
Randy Wolf Phi 27 4.35 4.71 10- 7
Jose Lima Hou 28 4.39 4.73 7-15
Kris Benson Pit 27 4.33 4.73 9-11
Kevin Tapani Chc 29 4.33 4.74 8-12
K. Bottenfield Phi 6 4.15 4.75 1- 2
Ismael Valdes Chc 12 4.47 4.78 2- 4
Jeff D'Amico Mil 18 4.49 4.82 11- 5
Ryan Dempster Fla 28 4.47 4.84 12- 9
Brian Bohanon Col 21 4.52 4.84 8 -9
Masato Yoshii Col 27 4.38 4.85 5-14
Curt Schilling Phi 16 4.57 4.90 6- 6
Reid Cornelius Fla 18 4.46 4.92 3 -8
National League easiest opponents
PITCHER TEAM G ERA RA Pitcher W-L
Jason Bere Mil 20 5.14 5.84 6- 7
Denny Neagle Cin 18 5.26 5.74 8- 2
Shane Reynolds Hou 22 5.10 5.66 7- 8
Shawn Estes SF 25 5.13 5.58 14- 4
Brian Meadows SD 22 5.09 5.58 7 -8
Steve Parris Cin 28 5.09 5.57 10-14
Ismael Valdes LA 7 5.01 5.57 0- 3
Todd Ritchie Pit 26 5.25 5.56 8- 7
Matt Clement SD 29 5.03 5.56 12-14
Ron Villone Cin 20 5.07 5.48 9- 8
Scott Elarton Hou 25 5.02 5.45 16- 5
John Burkett Atl 18 5.03 5.45 8- 6
Curt Schilling Ari 8 4.89 5.45 4- 5
Darren Dreifort LA 26 4.92 5.43 10- 8
Brian Anderson Ari 27 4.93 5.39 10- 5
Poor Steve Woodard. After escaping the National League having faced the toughest COP of any NL pitcher, he's already pacing the AL after seven starts. It's like he's facing Kevin Millwood or Gil Heredia every time out, while someone like Willie Blair gets to face Pat Rapp or Mike Thurman.
In all, Woodard faced Al Leiter, Tom Glavine, Darryl Kile, Shane Reynolds, Carl Pavano (twice), Freddy Garcia, Rick Helling, Rick Ankiel, Ryan Dempster, and Barry Zito for 11 of his 18 starts. The only pitcher with an ERA above 5.50 that Woodard faced was Anaheim's Seth Etherton, and in seven of his starts he faced a pitcher with a sub-4.00 ERA.
In contrast, Blair hasn't faced any starter with an ERA below 4.00, and he got to oppose Jaime Navarro twice. Blair has had a total of seven starts against pitchers with ERAs above 6.00. He has squared off against the likes of Jose Lima, Jamie Moyer, Darren Oliver, Ben Ford, Esteban Yan, and Clayton Andrews. Only Andy Pettitte, Brad Radke, Jimmy Anderson, Jose Mercedes, Kevin Appier and Kenny Rogers had ERAs below 4.60.
There's a fairly wide range between the hardest and easiest COPs, with some fortunate pitchers facing opposition that posts an RA 25-30 percent higher than the star-crossed hurlers. Even teammates can have radically different COPs. Roger Clemens has the fourth-toughest COP of any AL pitcher (10+ starts) with a COP RA of 5.03, while David Cone (5.82) and Andy Pettitte (5.78) are both in top 10 for easiest COP. Cone has squared off with opposing pitchers who were, on average, 15 percent worse than Clemens' opponents.
Two questions immediately come to mind when considering the list of Composite Opposing Pitchers. First, do star pitchers tend to face better opponents more often because the opposing manager juggles his rotation to pit ace against ace? Second, does a pitcher's COP profile have a measurable effect on the amount of support he gets from his teammates?
To answer the first question, I compared each pitcher's RA with his COP's RA, and looked at the correlation coefficient between the two. To explain the significance of this number in simple terms, when the correlation coefficient is near zero, there's no relationship between the two sets of values. As it approaches 1.0, there's a stronger and stronger relationship between the two sets of values.
For a pitcher's RA and his COP's RA, the correlation was only 0.16, meaning there is a very small relationship between how good a pitcher is and how good his Composite Opposing Pitcher is. If managers are trying to get those matchups, they aren't succeeding. Of course, with rotations more or less fixed save for the occasional off day, this isn't too surprising, nor is it obvious that it should be a strategic concern.
For the second question, I looked at a pitcher's run support (total number of runs scored in games started by the pitcher) and his COP's RA. Theoretically, if a pitcher is facing better opponents, his teammates should not do as well scoring runs in those games. For example, the Yankees scored 7.31 runs per game for Andy Pettitte and only 4.88 runs per game for Roger Clemens, and as we've seen, Clemens typically faced a much tougher opponent.
The correlation between a pitcher's run support and his COP's RA was 0.38, indicating a decent relationship between the quality of opponent a pitcher faces and the amount of run support he can expect. However, the offense is not off the hook yet. A correlation of 0.38 isn't all that great, and it still leaves plenty of room for hitters having more than their share of off days for certain pitchers. About 15 percent of the variation in run support is related to the differences in quality of Composite Opposing Pitchers. The rest has to do with which pitchers are lucky enough to throw on the days when the bats are hot.
Of course, a pitcher has no control over his COP, so this can be considered "luck" as well. But it is a different, quantifiable kind of luck that we can break out from other factors, and see if a pitcher faced more than his share of aces, or had it easy by going up against No. 5 starters. And after perusing the lists above, maybe you can agree that Steve Woodard deserves a break.
Keith Woolner may be reached at kwoolner@baseballprospectus.com. | |