wRC for Pitchers and Koji Uehara’s Dominance

wRC is a very useful statistic.  On the team level, it can be used to predict runs scored fairly accurately (r^2 of over .9).  It can also be used to measure how much a specific player has contributed to his team’s offensive production by measuring how many runs he has provided on offense.  But it is rarely used for pitchers.

Pitching statistics are not so much based on linear weights and wOBA as they are on defense-independent stats.  I think defense-independent stats are fine things to look at when evaluating players, and they can provide lots of information about how a pitcher really performed.  But while pitcher WAR is based off of FIP (at least on FanGraphs), RA9-WAR is also sometimes looked at.  Now, if the whole point of using linear weights for batters is to eliminate context and the production of teammates, then why not do the same for pitchers?  True, pitchers, especially starters, usually get themselves into bad situations, unlike hitters, who can’t control how many outs there are or who’s on base when they come up.  But oftentimes pitchers aren’t better in certain situations, as evidence by the inconsistency of stats such as LOB%.  So why not eliminate context from pitcher evaluations and look at how many runs they should have given up based on the hits, walks, and hit batters they allowed?

To do this, I needed to go over to Baseball-Reference, as FanGraphs doesn’t have easy-to-manipulate wOBA figures for pitchers.  Baseball-Reference doesn’t have any sort of wOBA stats, but what they do have is the raw numbers needed to calculate wOBA.  So I put them into Excel, and, with 50 IP as my minimum threshold, I calculated the wOBA allowed – and then converted that into wRC – for the 330 pitchers this year with at least 50 innings.

Next, I calculated wRC/9 the same way you would calculate ERA (or RA/9).  This would scale it very closely to ERA and RA/9, and give us a good sense for what each number actually means.  (The average wRC/9 with the pitchers I used was 3.95; the average RA/9 for the pitchers I used was 3.96).  What I found was that the extremes on both sides were way more extreme (you’ll see what I mean soon), but overall it correlated to RA/9 fairly closely (the r^2 was .803).

Now, for the actual numbers:

	wRC/9	IP
Koji Uehara	0.08	74.1
Tanner Roark	1.04	53.2
Joe Nathan	1.08	64.2
Greg Holland	1.17	67
Alex Torres*	1.24	58
Craig Kimbrel	1.41	67
Luis Avilan*	1.42	65
Neal Cotts*	1.43	57
Mark Melancon	1.52	71
Kenley Jansen	1.55	76.2
Clayton Kershaw*	1.59	236
Paco Rodriguez*	1.60	54.1
Luke Hochevar	1.65	70.1
Matt Harvey	1.69	178.1
Tyler Clippard	1.69	71
Jose Fernandez	1.80	172.2
Tony Watson*	1.89	71.2
J.P. Howell*	1.94	62
Bobby Parnell	2.00	50
Clay Buchholz	2.04	108.1
Glen Perkins*	2.09	62.2
Justin Wilson*	2.13	73.2
David Carpenter	2.13	65.2
Casey Janssen	2.15	52.2
Sean Doolittle*	2.16	69
Brandon Kintzler	2.17	77
Aroldis Chapman*	2.24	63.2
Luke Gregerson	2.29	66.1
Steve Cishek	2.30	69.2
Joaquin Benoit	2.31	67
Max Scherzer	2.32	214.1
Madison Bumgarner*	2.35	201.1
Sonny Gray	2.39	64
David Robertson	2.42	66.1
Jean Machi	2.44	53
Dane De La Rosa	2.46	72.1
Tyler Thornburg	2.56	66.2
Drew Smyly*	2.58	76
Jason Grilli	2.59	50
Stephen Strasburg	2.60	183
Danny Farquhar	2.64	55.2
Michael Wacha	2.66	64.2
Joel Peralta	2.67	71.1
Brett Cecil*	2.68	60.2
Brad Ziegler	2.69	73
Johnny Cueto	2.69	60.2
Tommy Hunter	2.69	86.1
Addison Reed	2.69	71.1
Bryan Shaw	2.72	75
Casey Fien	2.73	62
Mariano Rivera	2.77	64
Sergio Romo	2.81	60.1
Hisashi Iwakuma	2.81	219.2
Jose Veras	2.81	62.2
Cliff Lee*	2.81	222.2
Darren O’Day	2.82	62
Tanner Scheppers	2.85	76.2
Trevor Rosenthal	2.87	75.1
Yu Darvish	2.87	209.2
Adam Wainwright	2.88	241.2
Anibal Sanchez	2.88	182
Mike Dunn*	2.89	67.2
Jeanmar Gomez	2.90	80.2
Brian Matusz*	2.94	51
Charlie Furbush*	2.96	65
J.J. Hoover	2.97	66
Francisco Liriano*	2.98	161
Grant Balfour	2.99	62.2
Alfredo Simon	2.99	87.2
Jonathan Papelbon	3.04	61.2
Jesse Chavez	3.04	57.1
Tyson Ross	3.07	125
Gerrit Cole	3.07	117.1
A.J. Ramos	3.07	80
Craig Breslow*	3.07	59.2
Tom Wilhelmsen	3.07	59
Andrew Cashner	3.08	175
Chris Sale*	3.10	214.1
Felix Hernandez	3.10	204.1
Vin Mazzaro	3.10	73.2
Zack Greinke	3.11	177.2
Jim Henderson	3.12	60
Matt Albers	3.13	63
Sam LeCure	3.14	61
Anthony Swarzak	3.16	96
Jerry Blevins*	3.16	60
Henderson Alvarez	3.16	102.2
LaTroy Hawkins	3.17	70.2
Tony Cingrani*	3.17	104.2
Mike Minor*	3.18	204.2
Jordan Zimmermann	3.18	213.1
Tim Stauffer	3.21	69.2
Travis Wood*	3.21	200
Edward Mujica	3.21	64.2
Alex Cobb	3.22	143.1
Rex Brothers*	3.23	67.1
Justin Masterson	3.24	193
David Price*	3.24	186.2
Santiago Casilla	3.26	50
Ryan Cook	3.26	67.1
Brett Oberholtzer*	3.26	71.2
Bartolo Colon	3.27	190.1
A.J. Burnett	3.29	191
Danny Salazar	3.30	52
Josh Collmenter	3.31	92
Nate Jones	3.31	78
Chad Gaudin	3.33	97
Jamey Wright	3.33	70
Joe Smith	3.33	63
Homer Bailey	3.33	209
Marco Estrada	3.35	128
Hyun-jin Ryu*	3.36	192
Anthony Varvaro	3.36	73.1
Chad Qualls	3.38	62
Tim Hudson	3.38	131.1
Jarred Cosart	3.41	60
Scott Rice*	3.41	51
Chris Archer	3.42	128.2
Jake McGee*	3.43	62.2
Ervin Santana	3.48	211
Will Harris	3.48	52.2
Aaron Loup*	3.48	69.1
Yoervis Medina	3.50	68
Fernando Rodney	3.51	66.2
Huston Street	3.51	56.2
Burke Badenhop	3.51	62.1
Patrick Corbin*	3.53	208.1
Mat Latos	3.53	210.2
Ryan Webb	3.54	80.1
Jered Weaver	3.54	154.1
Rafael Soriano	3.56	66.2
Bruce Chen*	3.56	121
Scott Feldman	3.57	181.2
Shelby Miller	3.57	173.1
Alex Wood*	3.58	77.2
Matt Cain	3.59	184.1
Gio Gonzalez*	3.60	195.2
Craig Stammen	3.61	81.2
Hiroki Kuroda	3.62	201.1
Matt Moore*	3.62	150.1
Ryan Pressly	3.64	76.2
Dan Straily	3.64	152.1
A.J. Griffin	3.68	200
James Shields	3.68	228.2
Adam Ottavino	3.68	78.1
Pedro Strop	3.68	57.1
Cody Allen	3.68	70.1
Alexi Ogando	3.72	104.1
Jhoulys Chacin	3.73	197.1
Kyle Lohse	3.74	198.2
Jake Peavy	3.74	144.2
Cole Hamels*	3.76	220
Nathan Eovaldi	3.76	106.1
Carlos Torres	3.76	86.1
Andrew Albers*	3.78	60
Ricky Nolasco	3.80	199.1
Robbie Erlin*	3.80	54.2
Ross Ohlendorf	3.82	60.1
Dale Thayer	3.82	65
Jarrod Parker	3.85	197
Jose Quintana*	3.86	200
John Lackey	3.86	189.1
Julio Teheran	3.87	185.2
Cesar Ramos*	3.88	67.1
Ernesto Frieri	3.88	68.2
Steve Delabar	3.91	58.2
Ivan Nova	3.91	139.1
Matt Belisle	3.91	73
Ubaldo Jimenez	3.92	182.2
Kris Medlen	3.93	197
Wandy Rodriguez*	3.94	62.2
Kelvin Herrera	3.95	58.1
Justin Verlander	3.97	218.1
Garrett Richards	3.97	145
Charlie Morton	3.97	116
Matt Lindstrom	3.97	60.2
Tom Gorzelanny*	3.97	85.1
Jared Burton	3.97	66
Jeff Locke*	3.99	166.1
C.J. Wilson*	4.00	212.1
Tim Collins*	4.00	53.1
Seth Maness	4.00	62
Matt Garza	4.03	155.1
David Hernandez	4.03	62.1
Lance Lynn	4.04	201.2
Rick Porcello	4.04	177
Miguel Gonzalez	4.04	171.1
Carlos Villanueva	4.04	128.2
Derek Holland*	4.04	213
Robbie Ross*	4.05	62.1
Jim Johnson	4.05	70.1
Kevin Gregg	4.06	62
J.C. Gutierrez	4.08	55.1
Bryan Morris	4.09	65
Mike Leake	4.09	192.1
Joe Kelly	4.11	124
Zack Wheeler	4.11	100
Jon Lester*	4.12	213.1
Taylor Jordan	4.13	51.2
Bronson Arroyo	4.14	202
Tim Lincecum	4.15	197.2
Eric Stults*	4.17	203.2
Chris Tillman	4.18	206.1
Doug Fister	4.19	208.2
Junichi Tazawa	4.20	68.1
Corey Kluber	4.22	147.1
Logan Ondrusek	4.23	55
Jaime Garcia*	4.25	55.1
Tyler Lyons*	4.25	53
Jorge De La Rosa*	4.27	167.2
Yovani Gallardo	4.28	180.2
Wade Miley*	4.29	202.2
R.A. Dickey	4.30	224.2
James Russell*	4.30	52.2
Tyler Chatwood	4.32	111.1
Sam Deduno	4.33	108
Andy Pettitte*	4.35	185.1
Michael Kohn	4.37	53
Josh Outman*	4.38	54
Dillon Gee	4.38	199
Martin Perez*	4.39	124.1
Jake Arrieta	4.39	75.1
Shawn Kelley	4.39	53.1
Drew Storen	4.41	61.2
Preston Claiborne	4.42	50.1
Tommy Milone*	4.45	156.1
Wily Peralta	4.46	183.1
Scott Kazmir*	4.46	158
Felix Doubront*	4.54	162.1
Jeff Samardzija	4.55	213.2
Shaun Marcum	4.56	78.1
Dan Haren	4.58	169.2
Alfredo Figaro	4.58	74
Troy Patton*	4.60	56
Hector Rondon	4.62	54.2
Oliver Perez*	4.62	53
Trevor Cahill	4.63	146.2
Wei-Yin Chen*	4.63	137
Todd Redmond	4.64	77
Zach McAllister	4.64	134.1
Jonathon Niese*	4.65	143
Tom Koehler	4.65	143
Ronald Belisario	4.66	68
Jeremy Hefner	4.66	130.2
Jacob Turner	4.68	118
Kyle Kendrick	4.68	182
Chris Rusin*	4.70	66.1
Brandon McCarthy	4.70	135
Freddy Garcia	4.70	80.1
Randall Delgado	4.70	116.1
Wilton Lopez	4.72	75.1
Mark Buehrle*	4.73	203.2
T.J. McFarland*	4.74	74.2
J.A. Happ*	4.79	92.2
Jason Vargas*	4.80	150
David Phelps	4.81	86.2
Brian Duensing*	4.82	61
Hector Santiago*	4.84	149
CC Sabathia*	4.85	211
Nick Tepesch	4.88	93
Jeremy Hellickson	4.89	174
Wesley Wright*	4.93	53.2
Chris Capuano*	4.95	105.2
Donovan Hand	4.97	68.1
Jerome Williams	4.99	169.1
Adam Warren	5.01	77
Paul Maholm*	5.04	153
Jeremy Guthrie	5.08	211.2
Jonathan Pettibone	5.08	100.1
John Danks*	5.09	138.1
George Kontos	5.10	55.1
Edwin Jackson	5.10	175.1
Ian Kennedy	5.14	181.1
Brad Peacock	5.15	83.1
Bud Norris	5.16	176.2
Erik Bedard*	5.17	151
Travis Blackley*	5.18	50.1
Ryan Dempster	5.19	171.1
Kevin Correia	5.19	185.1
Erasmo Ramirez	5.20	72.1
Roberto Hernandez	5.20	151
Kevin Slowey	5.20	92
Aaron Harang	5.24	143.1
Jason Marquis	5.25	117.2
Jake Westbrook	5.27	116.2
Juan Nicasio	5.29	157.2
Heath Bell	5.35	65.2
Josh Roenicke	5.35	62
Esmil Rogers	5.38	137.2
John Axford	5.42	65
Mike Pelfrey	5.43	152.2
John Lannan*	5.45	74.1
Andre Rienzo	5.46	56
Ross Detwiler*	5.54	71.1
Jason Hammel	5.55	139.1
Stephen Fife	5.63	58.1
Edinson Volquez	5.65	170.1
Dallas Keuchel*	5.68	153.2
Jordan Lyles	5.70	141.2
Phil Hughes	5.71	145.2
Tommy Hanson	5.74	73
Luis Mendoza	5.79	94
Jeremy Bonderman	5.82	55
Brandon League	5.82	54.1
Roy Halladay	5.85	62
Chris Perez	5.94	54
Scott Diamond*	6.01	131
Ryan Vogelsong	6.04	103.2
Wade Davis	6.05	135.1
Justin Grimm	6.10	98
Paul Clemens	6.14	73.1
Lucas Harrell	6.23	153.2
Jeff Francis*	6.39	70.1
Brandon Morrow	6.39	54.1
Joe Saunders*	6.39	183
Jon Garland	6.40	68
Josh Johnson	6.45	81.1
Mike Gonzalez*	6.50	50
Wade LeBlanc*	6.54	55
Brandon Maurer	6.58	90
Barry Zito*	6.63	133.1
Carter Capps	6.64	59
Dylan Axelrod	6.82	128.1
Kyle Gibson	6.92	51
Joe Blanton	7.00	132.2
Clayton Richard*	7.14	52.2
Alex Sanabia	7.29	55.1
Tyler Cloyd	7.40	60.1
Philip Humber	7.62	54.2
Pedro Hernandez*	7.68	56.2
Average	3.95	110.2

The first thing that jumps out right away is that Koji Uehara had a wRC/9 of 0.08.  In other words, if that was his ERA, he would give up one earned run in about 12 complete game starts if he were a starter, which is ridiculous.  The second thing that jumps out is that most of the top performers are relievers – in fact, 12 out of the top 13 had fewer than 80 innings, with the only exception being Clayton Kershaw.  Also, the worst pitchers by wRC/9 had a wRC/9 much higher than their ERA or RA/9.  Pedro Hernandez, for example, had a wRC/9 of 7.68, and there were 6 pitchers over 7.00.  Kershaw actually has a wRC/9 that is lower than his insane RA/9, so maybe he’s even better than his fielding-dependent stats give him credit for.

But wait!  There’s more!  The reason we have xFIP is because HR/FB rates are very unstable.  So let’s incorporate that into our wRC/9 formula and see what happens (we’ll call this one xwRC/9):

	xwRC/9	IP
Koji Uehara	0.06	74.1
Paco Rodriguez*	1.13	54.1
Luke Hochevar	1.25	70.1
Tyler Clippard	1.25	71
Craig Kimbrel	1.51	67
Kenley Jansen	1.63	76.2
Aroldis Chapman*	1.68	63.2
Greg Holland	1.69	67
Casey Fien	1.88	62
Joe Nathan	2.06	64.2
Tanner Roark	2.06	53.2
Neal Cotts*	2.12	57
Clayton Kershaw*	2.13	236
Max Scherzer	2.17	214.1
Huston Street	2.18	56.2
Jose Fernandez	2.23	172.2
Alex Torres*	2.26	58
Yu Darvish	2.28	209.2
Glen Perkins*	2.29	62.2
Matt Harvey	2.32	178.1
Tony Watson*	2.35	71.2
Stephen Strasburg	2.35	183
Mark Melancon	2.36	71
Johnny Cueto	2.38	60.2
David Carpenter	2.39	65.2
Luis Avilan*	2.41	65
Justin Wilson*	2.48	73.2
Tommy Hunter	2.49	86.1
Joaquin Benoit	2.50	67
J.P. Howell*	2.51	62
David Robertson	2.52	66.1
Madison Bumgarner*	2.54	201.1
Hisashi Iwakuma	2.56	219.2
Tony Cingrani*	2.57	104.2
Jason Grilli	2.66	50
Darren O’Day	2.67	62
Jose Veras	2.68	62.2
Marco Estrada	2.70	128
Casey Janssen	2.71	52.2
Travis Wood*	2.76	200
Sonny Gray	2.80	64
Grant Balfour	2.81	62.2
Clay Buchholz	2.81	108.1
Danny Salazar	2.81	52
Cliff Lee*	2.81	222.2
Steve Cishek	2.83	69.2
Sean Doolittle*	2.83	69
Jim Henderson	2.83	60
Carlos Torres	2.84	86.1
Edward Mujica	2.85	64.2
Kelvin Herrera	2.86	58.1
Brett Cecil*	2.87	60.2
Jake McGee*	2.89	62.2
Mariano Rivera	2.89	64
Joel Peralta	2.89	71.1
Ernesto Frieri	2.93	68.2
Michael Wacha	2.95	64.2
Anibal Sanchez	2.95	182
Luke Gregerson	2.98	66.1
Brandon Kintzler	2.99	77
Tim Stauffer	2.99	69.2
Tanner Scheppers	2.99	76.2
Brad Ziegler	2.99	73
Alex Cobb	3.05	143.1
Dane De La Rosa	3.05	72.1
Addison Reed	3.06	71.1
Travis Blackley*	3.08	50.1
Jerry Blevins*	3.09	60
Bobby Parnell	3.09	50
Freddy Garcia	3.11	80.1
Jeanmar Gomez	3.13	80.2
Ervin Santana	3.17	211
Jean Machi	3.19	53
Trevor Rosenthal	3.20	75.1
J.J. Hoover	3.20	66
Chris Archer	3.20	128.2
Sergio Romo	3.20	60.1
Alfredo Figaro	3.21	74
Drew Smyly*	3.22	76
Alfredo Simon	3.23	87.2
Jonathan Papelbon	3.24	61.2
Charlie Furbush*	3.24	65
Mike Dunn*	3.26	67.2
Wandy Rodriguez*	3.26	62.2
Tyson Ross	3.27	125
Justin Masterson	3.27	193
Felix Hernandez	3.29	204.1
Mike Minor*	3.32	204.2
Rex Brothers*	3.33	67.1
Homer Bailey	3.33	209
Adam Wainwright	3.34	241.2
David Hernandez	3.34	62.1
Bryan Shaw	3.34	75
John Lackey	3.35	189.1
Danny Farquhar	3.36	55.2
Randall Delgado	3.37	116.1
Chris Sale*	3.37	214.1
LaTroy Hawkins	3.38	70.2
Chad Qualls	3.40	62
Jordan Zimmermann	3.41	213.1
Matt Cain	3.43	184.1
A.J. Griffin	3.45	200
Zack Greinke	3.45	177.2
Joe Smith	3.45	63
Burke Badenhop	3.46	62.1
Chris Tillman	3.47	206.1
Andrew Cashner	3.47	175
David Price*	3.49	186.2
Scott Feldman	3.49	181.2
Miguel Gonzalez	3.49	171.1
Francisco Liriano*	3.50	161
Nate Jones	3.51	78
Shelby Miller	3.51	173.1
Bronson Arroyo	3.52	202
Jake Peavy	3.52	144.2
Ross Ohlendorf	3.53	60.1
Tim Hudson	3.53	131.1
Logan Ondrusek	3.54	55
Yoervis Medina	3.54	68
Kyle Lohse	3.55	198.2
Tom Gorzelanny*	3.56	85.1
R.A. Dickey	3.58	224.2
Dale Thayer	3.59	65
Sam LeCure	3.60	61
Josh Collmenter	3.60	92
Aaron Loup*	3.61	69.1
Jesse Chavez	3.62	57.1
Hyun-jin Ryu*	3.62	192
A.J. Burnett	3.62	191
Brian Matusz*	3.62	51
Gerrit Cole	3.63	117.1
Bryan Morris	3.64	65
Pedro Strop	3.66	57.1
Patrick Corbin*	3.71	208.1
Hiroki Kuroda	3.72	201.1
Matt Moore*	3.74	150.1
Brett Oberholtzer*	3.75	71.2
Dan Straily	3.75	152.1
Julio Teheran	3.76	185.2
Alexi Ogando	3.76	104.1
Anthony Swarzak	3.76	96
Shawn Kelley	3.77	53.1
Jered Weaver	3.79	154.1
Ryan Webb	3.81	80.1
Jaime Garcia*	3.82	55.1
Gio Gonzalez*	3.82	195.2
Matt Albers	3.83	63
Kris Medlen	3.84	197
Matt Garza	3.86	155.1
Jamey Wright	3.86	70
Craig Breslow*	3.88	59.2
Cody Allen	3.88	70.1
Preston Claiborne	3.89	50.1
Cole Hamels*	3.91	220
Rafael Soriano	3.91	66.2
A.J. Ramos	3.92	80
Bruce Chen*	3.93	121
Santiago Casilla	3.93	50
Todd Redmond	3.94	77
Rick Porcello	3.94	177
Bartolo Colon	3.95	190.1
Dan Haren	3.99	169.2
John Danks*	3.99	138.1
Craig Stammen	4.00	81.2
Tyler Thornburg	4.00	66.2
Fernando Rodney	4.00	66.2
Chad Gaudin	4.01	97
Will Harris	4.01	52.2
Tommy Milone*	4.01	156.1
James Russell*	4.01	52.2
Jarred Cosart	4.02	60
Robbie Erlin*	4.02	54.2
Troy Patton*	4.03	56
Scott Rice*	4.03	51
James Shields	4.03	228.2
Mike Leake	4.05	192.1
Jared Burton	4.05	66
Ubaldo Jimenez	4.05	182.2
Seth Maness	4.05	62
Jeremy Hefner	4.06	130.2
Vin Mazzaro	4.06	73.2
Tim Lincecum	4.07	197.2
Mat Latos	4.08	210.2
Junichi Tazawa	4.10	68.1
Eric Stults*	4.10	203.2
Garrett Richards	4.12	145
Adam Ottavino	4.12	78.1
Zack Wheeler	4.13	100
Andrew Albers*	4.15	60
Carlos Villanueva	4.16	128.2
Andre Rienzo	4.16	56
Jeff Samardzija	4.18	213.2
Jake Arrieta	4.20	75.1
Tom Wilhelmsen	4.21	59
Jim Johnson	4.21	70.1
Brad Peacock	4.22	83.1
Corey Kluber	4.22	147.1
Heath Bell	4.22	65.2
Wade Miley*	4.25	202.2
Michael Kohn	4.25	53
Martin Perez*	4.26	124.1
Ricky Nolasco	4.26	199.1
Matt Belisle	4.27	73
Charlie Morton	4.27	116
Jon Lester*	4.27	213.1
Scott Kazmir*	4.27	158
Roberto Hernandez	4.28	151
Jarrod Parker	4.28	197
Justin Verlander	4.29	218.1
Derek Holland*	4.31	213
Henderson Alvarez	4.31	102.2
Ryan Cook	4.32	67.1
Cesar Ramos*	4.33	67.1
Ivan Nova	4.33	139.1
Jeff Locke*	4.34	166.1
Andy Pettitte*	4.35	185.1
Ryan Pressly	4.36	76.2
Yovani Gallardo	4.36	180.2
Donovan Hand	4.36	68.1
Dillon Gee	4.38	199
Drew Storen	4.39	61.2
Alex Wood*	4.39	77.2
Tyler Lyons*	4.40	53
Nathan Eovaldi	4.41	106.1
Kevin Gregg	4.42	62
Wesley Wright*	4.43	53.2
Jose Quintana*	4.43	200
Anthony Varvaro	4.44	73.1
Steve Delabar	4.44	58.2
Jason Marquis	4.46	117.2
Oliver Perez*	4.48	53
Wily Peralta	4.48	183.1
Joe Kelly	4.49	124
Lance Lynn	4.49	201.2
J.C. Gutierrez	4.53	55.1
Roy Halladay	4.54	62
Jhoulys Chacin	4.54	197.1
C.J. Wilson*	4.55	212.1
Chris Rusin*	4.56	66.1
Erasmo Ramirez	4.56	72.1
Doug Fister	4.58	208.2
Aaron Harang	4.59	143.1
Hector Rondon	4.60	54.2
CC Sabathia*	4.60	211
T.J. McFarland*	4.62	74.2
Jeremy Hellickson	4.62	174
Sam Deduno	4.64	108
Nick Tepesch	4.64	93
Ian Kennedy	4.65	181.1
Wei-Yin Chen*	4.68	137
Robbie Ross*	4.68	62.1
Chris Perez	4.69	54
Jerome Williams	4.69	169.1
Trevor Cahill	4.70	146.2
Adam Warren	4.71	77
Hector Santiago*	4.75	149
Taylor Jordan	4.77	51.2
Ryan Dempster	4.79	171.1
Esmil Rogers	4.80	137.2
John Axford	4.80	65
Tim Collins*	4.81	53.1
Jeremy Guthrie	4.81	211.2
Tom Koehler	4.83	143
Matt Lindstrom	4.84	60.2
Felix Doubront*	4.86	162.1
Jorge De La Rosa*	4.89	167.2
Jason Vargas*	4.89	150
Paul Clemens	4.95	73.1
J.A. Happ*	4.95	92.2
Erik Bedard*	4.96	151
Paul Maholm*	4.97	153
Josh Outman*	4.99	54
Jacob Turner	5.00	118
Tyler Chatwood	5.00	111.1
Shaun Marcum	5.00	78.1
George Kontos	5.03	55.1
Jason Hammel	5.04	139.1
Brandon McCarthy	5.06	135
Zach McAllister	5.06	134.1
Brandon Morrow	5.13	54.1
Jonathon Niese*	5.17	143
Brandon League	5.17	54.1
David Phelps	5.18	86.2
Chris Capuano*	5.18	105.2
Clayton Richard*	5.21	52.2
Carter Capps	5.21	59
Ronald Belisario	5.26	68
Wilton Lopez	5.27	75.1
Dallas Keuchel*	5.28	153.2
Jonathan Pettibone	5.28	100.1
Juan Nicasio	5.34	157.2
Stephen Fife	5.34	58.1
Edwin Jackson	5.36	175.1
Mike Gonzalez*	5.39	50
Kevin Slowey	5.40	92
Josh Johnson	5.42	81.1
Phil Hughes	5.42	145.2
Mark Buehrle*	5.45	203.2
Bud Norris	5.46	176.2
Brian Duensing*	5.51	61
Josh Roenicke	5.52	62
Jeff Francis*	5.62	70.1
Scott Diamond*	5.64	131
Jordan Lyles	5.65	141.2
Justin Grimm	5.66	98
Tommy Hanson	5.67	73
Kevin Correia	5.67	185.1
Edinson Volquez	5.69	170.1
Lucas Harrell	5.72	153.2
Joe Blanton	5.73	132.2
Brandon Maurer	5.80	90
John Lannan*	5.85	74.1
Ryan Vogelsong	5.85	103.2
Jeremy Bonderman	5.87	55
Luis Mendoza	5.88	94
Kyle Kendrick	5.90	182
Jake Westbrook	5.93	116.2
Mike Pelfrey	5.95	152.2
Dylan Axelrod	6.11	128.1
Jon Garland	6.21	68
Wade Davis	6.22	135.1
Ross Detwiler*	6.24	71.1
Joe Saunders*	6.29	183
Alex Sanabia	6.62	55.1
Barry Zito*	6.63	133.1
Wade LeBlanc*	6.65	55
Kyle Gibson	6.70	51
Philip Humber	7.19	54.2
Pedro Hernandez*	7.32	56.2
Tyler Cloyd	7.73	60.1
Average	3.99	110.2

Not a huge difference, although we do see Uehara’s number go down, which is incredible, and Tanner Roark’s – the second-best pitcher by wRC/9 – nearly double.  Also, Tyler Cloyd becomes much worse, and is now the worst pitcher by almost half a run per nine innings.  Kershaw’s wRC/9 goes up by a considerable amount, so much so that his xwRC/9 is now higher than his RA/9.  All in all, however, xwRC/9 actually has a smaller correlation with RA/9 (an r^2 of .638) than wRC/9 does, so it isn’t as useful. 

Now, logically, the people who outperformed their wRC/9 the most would have high strand (LOB) rates, and vice-versa.  So let’s look at the ten players who both outperformed and underperformed their wRC/9 the most.  The ones who underperformed:

	IP	LOB%	RA/9	wRC/9	RA/9 – wRC/9
Danny Farquhar	55.2	58.50%	4.69	2.64	2.05
Charlie Furbush	65	64.40%	4.57	2.96	1.61
Casey Fien	62	69.40%	4.06	2.73	1.33
Andrew Albers	60	60.40%	5.10	3.78	1.32
Nate Jones	78	62.90%	4.62	3.31	1.31
Joel Peralta	71.1	70.20%	3.91	2.67	1.24
Addison Reed	71.1	68.90%	3.91	2.69	1.22
Tom Wilhelmsen	59	69.90%	4.27	3.07	1.20
Jesse Chavez	57.1	66.90%	4.24	3.04	1.19
Koji Uehara	74.1	91.70%	1.21	0.08	1.13

We can see that everyone here – except for Koji Uehara, who had the fourth-highest LOB% out of all pitchers with 50 innings – is below the league average of 73.5%.  Only Uehara and Joel Peralta are above 70%.  Clearly, a low LOB% makes you allow many more runs than you should.  But what about Koji Uehara?  How did he allow all those runs (10, yeah, not a lot, but his wRC/9 was way lower than his RA/9) without allowing many baserunners to score and not allowing many damaging hits?  If you know, let me know in the comments, because I have no idea.

Now for the people who outperformed their wRC/9:

Rex Brothers	67.1	88.80%	2.14	3.23	-1.09
Donovan Hand	68.1	81.90%	3.82	4.97	-1.15
Stephen Fife	58.1	78.40%	4.47	5.63	-1.16
Jarred Cosart	60	85.90%	2.25	3.41	-1.16
Heath Bell	65.2	82.70%	4.11	5.35	-1.23
Chris Perez	54	82.30%	4.50	5.94	-1.44
Mike Gonzalez	50	80.30%	5.04	6.50	-1.46
Seth Maness	62	84.50%	2.47	4.00	-1.53
Adam Warren	77	84.70%	3.39	5.01	-1.62
Alex Sanabia	55.1	77.40%	5.37	7.29	-1.93

Just what you would expect:  high LOB%’s from all of them (each is above the league average).  Stephen Fife and Alex Sanabia are the only ones below 80%.

So what does this tell us?  I think it’s a better way to evaluate pitchers than runs or earned runs allowed since it eliminates context:  a pitcher who lets up a home run, then a single, then three outs is not necessarily better than one who lets up a single, home run, then three outs, but the statistics will tell you he is.  It might not be as good as an evaluator as FIP, xFIP, or SIERA, but for a fielding-dependent statistic, it might be as good as you can find.

Note:  I don’t know why the pitchers with asterisks next to there name have them; I copied and pasted the stats from Baseball-Reference and didn’t bother going through and removing the asterisks.