WAR by Age--A Pitching Analysis

A couple of weeks ago, I posted on the career WAR trend for position players. I may revisit the topic as ideas have popped into my mind (separating power hitters from defensive specialists, etc.), but it was always my intention to discuss the same subject with respect to pitchers. It will be trickier, since the modern era has introduced specialization that is far beyond anything seen on the offensive side. As such, I'll break down pitching by two categories:

1. Starting--I just changed my criteria as I wrote this. I was initially going to include anyone who made at least 20 starts in a season, and had I done that, this would have created a compilation of around 9,000 seasons. I didn't particularly like this for any number of reasons and decided to expand it to ANY start between 1901-2012. This will probably lower the average WAR figures but give a more realistic picture.

2. Relief--I also just changed my criteria as I wrote this, but I'm less sure on this. I was initially going to create two relief categories (closer and middle) and define closer as any season with 10+ saves. I really didn't like that, and understand fully that relief pitching will only really matter beginning around 1975 or so, but I've decided again to widen it and include any pitching season with at least one save. Again, this will likely dilute the values, but it will be across the board. I may run this one also with the 10+ save criteria to see if any differences arise.

STARTING PITCHERS

I've changed my mind again--this chart shows every pitcher who made at least one start in a year from 1901-2012:

This is a two-axis chart, with the number of pitchers who made at least one start at a given age on the left and the average WAR on the right. If you read the previous post on position players referenced above, the age distribution should look very familiar--the number of pitchers peaks at age 25, when about 2500 have made at least one start and begins a rather steady decline. I would absolutely LOVE to have pitch count data for this time frame, but reliable data only goes back to 1988. 

The red line is average WAR, and that does something very different than in position players--it gradually increases until somewhere around age 32-33 and then stays at a very steady plateau until around 37. I stop at that age because at that point, the effect I described among position players begins, which is that pitchers at 37 or more aren't pitching because teams need roster spots filled, but because they're effective--if they're not effective, THEY'RE NOT IN THE MAJOR LEAGUES. This is why there's no precipitous drop-off in performance--if there was, they'd simply be released. What is stunning is that gradual increase in performance that begins around 22-23.

I was going to show a second chart, but the story is simply told--of the games these pitchers were in, they started about 60% of games, a number that held remarkably steady through the age. Now I'll show the next chart, which is those seasons in which the pitcher made at least 20 starts:

I didn't do something similar with the position players, which would have been the equivalent of them having to have at least 300 plate appearances or something  like that. In effect, I've selected out the best of the best, since a pitcher simply won't make 20 starts if they're not effective. These seasons peak at about the same age and begin the same precipitous decline afterward. The spikes are ages 40 and 45 are the Roger Clemens and Nolan Ryan effects, respectively, with a little love for Warren Spahn as well. 

The very same pattern with position players is represented--if a pitcher in his 30s continues to perform, he'll still be pitching, but the numbers suggest that it's not easy to maintain. This is a selection of those 35-year-old pitchers from modern times:

Rk	Player	Year	GS	Age	Tm	G	CG	SHO	W	L	W-L%	IP	H	R	ER	BB	SO	ERA	ERA+
1	Ryan Dempster	2012	28	35	TOT	28	0	0	12	8	.600	173.0	155	71	65	52	153	3.38	125
2	A.J. Burnett	2012	31	35	PIT	31	1	1	16	10	.615	202.1	189	86	79	62	180	3.51	106
3	Randy Wolf	2012	26	35	TOT	30	0	0	5	10	.333	157.2	196	103	99	52	104	5.65	73
4	Bruce Chen	2012	34	35	KCR	34	0	0	11	14	.440	191.2	215	114	108	47	140	5.07	82
5	Bronson Arroyo	2012	32	35	CIN	32	1	1	12	10	.545	202.0	209	86	84	35	129	3.74	112
6	Roy Halladay	2012	25	35	PHI	25	0	0	11	8	.579	156.1	155	78	78	36	132	4.49	90
7	Carl Pavano	2011	33	35	MIN	33	3	1	9	13	.409	222.0	262	123	106	40	102	4.30	94
8	Ted Lilly	2011	33	35	LAD	33	0	0	12	14	.462	192.2	172	88	85	51	158	3.97	93
9	Tim Hudson	2011	33	35	ATL	33	1	1	16	10	.615	215.0	189	86	77	56	158	3.22	119
10	Kevin Millwood	2010	31	35	BAL	31	1	0	4	16	.200	190.2	223	116	108	65	132	5.10	81
11	R.A. Dickey	2010	26	35	NYM	27	2	1	11	9	.550	174.1	165	62	55	42	104	2.84	138
12	Chris Carpenter	2010	35	35	STL	35	1	0	16	9	.640	235.0	214	99	84	63	179	3.22	120
13	Hiroki Kuroda	2010	31	35	LAD	31	0	0	11	13	.458	196.1	180	87	74	48	159	3.39	114
14	Livan Hernandez	2010	33	35	WSN	33	2	1	10	12	.455	211.2	216	93	86	64	114	3.66	110
15	Derek Lowe	2008	34	35	LAD	34	1	0	14	11	.560	211.0	194	84	76	45	147	3.24	129
16	Andy Pettitte	2007	34	35	NYY	36	0	0	15	9	.625	215.1	238	106	97	69	141	4.05	112

Provided by Baseball-Reference.com: View Play Index Tool Used
Generated 5/24/2013.

 

Not too many power pitchers in that group, but pitchers who were able to use location, guile and experience to have success. It's safe to say that if they weren't successful, they wouldn't be on major league rosters, let alone making 20 or more starts.

17 pitchers made 20 or more starts at the age of 19:

Rk	Player	Year	GS	Tm	G	CG	SHO	W	L	IP	H	R	ER	BB	SO	ERA	ERA+
1	Dwight Gooden	1984	31	NYM	31	7	3	17	9	218.0	161	72	63	73	276	2.60	137
2	David Clyde	1974	21	TEX	28	4	0	3	9	117.0	129	64	57	47	52	4.38	81
3	Bert Blyleven	1970	25	MIN	27	5	1	10	9	164.0	143	66	58	47	135	3.18	119
4	Gary Nolan	1967	32	CIN	33	8	5	14	8	226.2	193	73	65	62	206	2.58	147
5	Larry Dierker	1966	28	HOU	29	8	2	10	8	187.0	173	73	66	45	108	3.18	108
6	Catfish Hunter	1965	20	KCA	32	3	2	8	8	133.0	124	68	63	46	82	4.26	82
7	Wally Bunker	1964	29	BAL	29	12	1	19	5	214.0	161	72	64	62	96	2.69	134
8	Ray Sadecki	1960	26	STL	26	7	1	9	9	157.1	148	76	66	86	95	3.78	108
9	Milt Pappas	1958	21	BAL	31	3	0	10	10	135.1	135	67	61	48	72	4.06	89
10	Mike McCormick	1958	28	SFG	42	8	2	11	8	178.1	192	103	91	60	82	4.59	84
11	Curt Simmons	1948	23	PHI	31	7	0	7	13	170.0	169	110	92	108	86	4.87	81
12	Hal Newhouser	1940	20	DET	28	7	0	9	9	133.1	149	81	72	76	89	4.86	98
13	Bob Feller	1938	36	CLE	39	20	2	17	11	277.2	225	136	126	208	240	4.08	113
14	Frank Shellenback	1918	21	CHW	28	10	2	9	12	182.2	180	77	54	74	47	2.66	103
15	Pete Schneider	1915	35	CIN	48	16	5	14	19	275.2	254	110	76	104	108	2.48	116
16	Ray Keating	1913	21	NYY	28	9	2	6	12	151.1	147	77	54	51	83	3.21	93
17	Chief Bender	1903	33	PHA	36	29	2	17	14	270.0	239	115	92	65	127	3.07	100

Provided by Baseball-Reference.com: View Play Index Tool Used
Generated 5/22/2013.

With very few exceptions (Clyde the obvious one and I know absolutely nothing about those three right after Bob Feller), these are solid-to-Hall of Fame pitchers. This is not unusual--anyone able to perform at that level at that age can be reasonably expected to have a stellar career, but it's a much more certain pattern with hitters than with pitchers.

These are the best seasons by age since 1950--prior to that and the list is dominated by early 20th Century pitchers:

I won't say it definitely, but I suspect that many will be surprised to see Wilbur Wood on this list in two spots--he was part of that iron-man renaissance that briefly arose in the 1970s when pitchers were throwing 275 or more innings. I just read it (again) in Bill James' Historical Abstract, but consider the following table of number of pitchers throwing 275 or more innings in a season by decade:

The phenomenon is well-known with NFL running backs that they lose effectiveness right around age 30, but since players enter the NFL at approximately the same age of 22-23, it's entirely possible that there is a NUMBER OF PLAYS wall that players hit, and that the wall sits right at the 30-year mark. It could be that pitchers have a "finite" number of pitches in their arms absent freaks of nature like Nolan Ryan, rubber-armed wonders like Wilbur Wood or simply once-in-a-generation talent like Randy Johnson or Greg Maddux. It's a little-known fact that Hall of Famers become so usually by defying traditional age trends--that's what makes them special.

So what will major league teams do with regard to starting pitching--will they replicate recent trends of locking in good young talent to avoid free agency? In some cases this is happening, which the White Sox doing so over the past couple of years with Chris Sale, John Danks and Gavin Floyd with decidedly mixed results--Sale just missed a start, Danks is scheduled to make his first start in over a year and Floyd is out for the year and potentially done with the Sox--around a combined $25 million commitment that hasn't produced. 

It could be that baseball follows the trend with football--draft a running back, ANY running back, run him into the ground for four or five years, reload and go again. The running back has been de-emphasized and big dollar contracts, at least for now, are hard to find. Baseball might do that with pitchers--throw out young pitchers and get what can be had, keep the truly special ones that are able to maintain productivity past the age of 30 (Justin Verlander, Roy Halladay, even though he's clearly on the decline now, same for Cliff Lee, CC Sabathia, etc.). Spend the money on perceived future performance and stay away from the Barry Zito-like contracts that simply will not be repeated going forward. In every generation, there will be a Tom Glavine or Mike Mussina that are able to have long, productive careers with few discernible signs of productivity loss, but they are exceptions.