Mariano Rivera - Era-Adjusted Home Runs (HR/9) Using HR-Plus

An earlier post - Mariano Rivera's Nasty Statistics - discussed Mariano's high rankings in several statistical categories. Since statistics such as strikeouts, home run rates, and runs scored have varied so much across MLB history, I've been working on a mini-project to normalize these stats across eras, primarily for the all-important purpose of seeing where Mariano ranks. This post presents the career leaders in adjusted Home runs per nine innings (HR/9).

Using actual stats, Mariano's .47 HR/9 ranked a seemingly mortal 264th out of the 1037 pitchers who have pitched at least 1000 innings since 1901. However, since Mariano has pitched in the highest HR environment of all time, looking at adjusted stats underrates Mariano. For example, Hall of Famer Rube Marquard had a .291 career HR/9, ranking him well above Mariano. But Marquard pitched from 1908-1925, where the average HR/9 was .235. So Marquard was actually 20% worse than league average at preventing HRs, while Mariano's .47 HR/9 is more than twice as good at the league average from 1995-2011 (which was a 1.064 HR/9).

To see beyond such distortions, we need to adjust the pitchers' HR/9 stats to a common scale. In this exercise, I adjusted career HR/9 stats to the 1953 AL, which I chose because that league averaged a HR/9 of .715, which is almost identical to the MLB historical average HR/9 of .714. (Note: The method would rank pitchers the same regardless of which year and league used as the adjustment target.)

To adjust, I used the Home Runs Plus (HR+) statistic, which is one of the "Plus" statistics Diamond Mind Baseball uses to adjust for era differences. HR+ measures how far above or below average a given pitcher's HR/9 in a season was to the league average - a score of 100 is average, above 100 is above average, etc. For example, in 2011 Mariano's HR+ was 224, indicating he was 124% better than the 2011 AL league average in preventing home runs.

Once you have pitchers' annual HR+ stats, you can use that data to calculate pitchers' career HR+ stats. You can then use career HR+ stats to adjust pitchers HRs allowed and HR/9 for a given season's HR rate, which provides the needed common scale mentioned earlier. To spare those who are averse to math and are just interested in the results, the calculation method is described on a separate page - see http://www.guttygrittyyankees.com/p/adjusting-career-home-runs-allowed-hr9.html.

The following table lists the top 25 pitchers in MLB history in HR+,  for pitchers with at least 1000 IP through 2011, and also adjusted HRs allowed and HR/9 to the 1953 AL. Mariano ranks 4th - his HR+ of 228 indicates he was 128% better than league average at preventing HRs.

Pitcher	Debut	IP	HRs	HR/9	Expected HRs	HR+	Adjusted HRs	Adjusted HR/9
Corridon, Frank	1904	1216.0	7	0.052	18	262	37	0.273
Pfiester, Jack	1903	1067.3	6	0.051	15	251	34	0.285
Russell, Reb	1913	1291.7	7	0.049	17	244	42	0.294
Rivera, Mariano	1995	1211.3	65	0.483	148	228	42	0.313
Killian, Ed	1903	1598.3	9	0.051	20	219	58	0.327
Minton, Greg	1975	1130.7	43	0.342	93	216	42	0.331
Perranoski, Ron	1961	1174.7	50	0.383	105	210	44	0.340
May, Jakie	1917	1562.3	35	0.202	71	204	61	0.350
Wood, Joe	1908	1436.3	10	0.063	20	204	56	0.350
Rixey, Eppa	1912	4494.7	92	0.184	184	200	178	0.357
McDowell, Roger	1985	1050.0	50	0.429	96	191	44	0.374
Ruth, Babe	1914	1221.3	10	0.074	18	180	54	0.398
Tekulve, Kent	1974	1436.3	63	0.395	113	179	64	0.399
Veale, Bob	1962	1926.0	91	0.425	162	178	86	0.402
Joss, Addie	1902	2327.0	19	0.073	33	175	106	0.409
Forster, Terry	1971	1105.7	51	0.415	88	173	51	0.412
Quisenberry, Dan	1979	1043.3	59	0.509	102	172	48	0.415
Brown, Kevin	1986	3256.3	208	0.575	358	172	150	0.416
Donahue, Red	1893	1535.0	17	0.100	29	171	71	0.418
Plank, Eddie	1901	4495.7	41	0.082	70	170	210	0.420
Wight, Bill	1946	1563.0	74	0.426	125	169	73	0.422
Webb, Brandon	2003	1319.7	92	0.627	156	169	62	0.423
Lincecum, Tim	2007	1028.0	66	0.578	111	169	48	0.423
Richard, J.R.	1971	1606.0	73	0.409	123	169	76	0.423
Hollingsworth, Al	1935	1520.3	47	0.278	79	168	72	0.425

 I posted a spreadsheet listing these stats for all pitchers with at least 1000 IP - see https://docs.google.com/spreadsheet/ccc?key=0AkMu391-e5t0dDdlTjhaNlVpZWI1anBqVklWTlBLb3c.

There are many interesting things about the list. For example, apart from being exceptionally good at preventing HRs, what do Frank Corridon and Mariano Rivera have in common?

Phil Hughes, and All the Pseudo-News that Is Fit To Print

My reaction to Phil Hughes' poor 3.1 inning performance yesterday, since it fit into his declining trendline as a starter since last season, was that while we might find that Hughes' stuff translates to a reliever who faces batters once a game, it is way too premature to stick a fork into a promising 26-year-old starter who has already had success in the major leagues. Moreso since the Yankee starting rotation includes a 38-year-old pitcher who has only hitherto pitched in the NL West and a 35-year-old junkballer whose only start this year seemed a homage to the pitching style of AJ Burnett.

The Yankees will face decisions when Andy Pettitte and Michael Pineda  are ready; but until then, there's no reason to rush to a decision on Phil Hughes, especially since his stuff has looked good and his changeup seems to be developing.

And indeed, thinking of Pettitte reminded me of when he was approximately Hughes' age; a poor end to the 1998 season and a poor first half of 1999, culminating in a dreadful 3.1 inning start against the White Sox, led to numerous rumors that the Yankees would trade Pettitte in a 1980s-Yankees-style manner of trading youth for declining veterans.

So this morning, when reading the NY Times I almost spit out my coffee when reading this sentence:

     "Hughes had an impressive spring but his two ineffective outings, coupled with a poor season last year... are already raising questions about his long-term viability."

Were Girardi and/or Cashman hitting the panic button? Fortunately it turned out that there is nothing here that could be described as actual news - the only actual Yankee information in the article is this:

     "Manager Joe Girardi, however, bristled at suggestions that Hughes was in danger of losing his starting spot after only two outings."

This conflation of gossip and news is why I so disrespect the baseball media, it unfortunately is all too typical. What happens is that the reporters express their questions and concerns as having an objective reality. A common device is to use passive sentences such as "...are already raising questions about his long-term viability" to deceive the reader into thinking the reporter is reporting on news from an objective source such as a decision-maker. The reality however is that the reporter is merely reporting that his fellow colleagues are the only ones asking this question, information which the passive sentence omits.

Now it is fine for reporters to ask questions and to refer to that in articles; it is the presentation here that is dishonest. If the reporter considered this question worth reporting on at all, the accurate way to describe it is that Girardi was asked, and his response was essentially that it was a stupid question to ask after only 2 starts.

Joel Sherman Rips A-Rod and Enhances Our Understanding of Infinity

Voltaire famously wrote that:

     "The only way to comprehend what mathematicians mean by Infinity is to contemplate the extent of human stupidity."

I've long felt that above quote could be paraphrased as follows when talking to baseball fans:

     "The only way to comprehend what mathematicians mean by Infinity is to contemplate the extent of stupidity expressed in the New York newspapers' sports pages."

Today's Joel Sherman article, A-Rod HRs help, hurt Yankees, is a perfect example. Sherman says the following about A-Rod's pursuit of the all-time HR record:

     "It would be best for both team and player if Rodriguez gets in the left lane and passes every one of those historic figures while it also looms as a dreadful proposition for all involved."

The reason Sherman considers it a "dreadful proposition" is because of A-Rod's admission of PED usage for a few years when a Texas Ranger. The evidence he cites is that a parade did not break out when A-Rod tied Ken Griffey at 630 HRs:

     "There was no confetti. No sustained applause. No waiting call of congratulations from Griffey."

Earth to Joel Sherman: no one cares about Ken Griffey Jr.'s all-time HR ranking of 5th. Every time someone gets passed on a list is not parade-worthy. For example, I don't recall a celebration occurring after Griffey passed Frank Robinson to move into 6th place in 2007.

I will make a few bold predictions regarding what will happen in the real world if A-Rod breaks the all-time HR record:

• If A-Rod passes Bonds, Aaron, and Ruth, it means he will be contributing to a lot of Yankee wins over the next several seasons. 
• Contributing to a lot of Yankee wins should make A-Rod kind of popular.
• That level of popularity will make breaking these records a fun event for Yankee fans.

If you need evidence, look at the video of A-Rod's 600th HR. This occurred the season after A-Rod admitted his PED use. The fan reaction does not exactly strike me as an example of a "dreadful proposition."

All it really means is that like most of the beat writers, Joel Sherman often projects his own feelings onto fans. A perfect example is Sherman's reaction to A-Rod's 600th HR:

     "Alex Rodriguez never is going to be fully a Yankee. He never is going to be fully appreciated as a clean homer giant. He never is going to be beloved in a Hank Aaron kind of way."

Contrast that observation to the video linked above, which shows the response of actual paying Yankee fans to #600. The extended standing ovation is an odd way for fans to express their disapproval of A-Rod's supposed lack of "True Yankee-ness."

Thinking about this inspires me to one last bold prediction: The Joel Shermans of the baseball media will write of the record-breaking moment being a "dreadful proposition". This is so predictable that this group should just stay home if and when A-Rod is sitting on his 763rd HR,since they will write the same article regardless of whether or not they actually see the event.

Statistics and Girardi's Opening Day Intentional Walk Decision

Joe Girardi explained his decision to intentionally walk Sean Rodriguez and load the bases for Carlos Pena as follows:

   "Sean Rodriguez has hit (Sabathia) hard."

Of course if CC Sabathia executed his pitches, Pena would not have hit a grand-slam. However, that does not absolve Girardi from his responsibility for reading the current situation, which I saw as this:

• CC was struggling with his command.
• An intentional walk loads the bases, thus putting pressure on the pitcher to command his pitches.
• Carlos Pena has a good eye, as measured by his ability to draw walks, thus exacerbating said pressure.
• In that context, to me the only way an intentional walk is sane is if Sean Rodriguez were unarguably, significantly worse of a match up than Pena.

Girardi's justification was in the pitcher-hitter match ups, so let's look at some pertinent batter-vs.-Sabathia match up statistics:

Player	AB	H	D	T	HR	K	BA	SLG	BABIP	ISO
Rodriguez	21	6	2	0	1	5	.286	.524	.333	.238
Pena	35	4	1	0	2	19	.114	.314	.143	.200

The conventional batting average and slugging percentage stats suggest Rodriguez is significantly better against Sabathia than Pena. But that is superficial - the overall data also suggest this is merely an illusion, for these reasons:

• Pena's low BABIP suggests Pena may have just had rather poor luck against CC.
• The ISO stats suggest that both hitters have hit CC pretty much equally in terms of power.

Of course it's risky to read too much into the small sample sizes that typically constitute batter-vs.-pitcher match ups; but if you are going to look at such stats, stats such as BABIP and ISO give one some insight into how meaningful (or meaningless) they might be. 

Note: We don't know whether Girardi was looking at the above statistics, or some more sophisticated data. But we do know that whatever the stats were, they were of a small sample size. We also know that they could not have indicated CC owned Pena - if CC owned Pena he would not have given up 2 HRs in 35 ABs.

In this case, since Pena is a much more dangerous hitter than Rodriguez, and given the context of CC struggling with his command, etc., the intentional walk seems merely an abuse of whatever data Girardi was using to make this decision.

Yankees Place Intentional Walk Restriction On Girardi

Brian Cashman announced that "Joe Girardi is no longer allowed to walk players with a last name of Rodriguez unless that player is worthy of a '-Rod' nickname, such as A-Rod."

This of course is in response to the first inning of Opening Day, when Girardi ordered (or allowed) his ace to intentionally walk the immortal Sean Rodriguez to load the bases for slugger Carlos Pena.

Rodriguez's career line is .229/.307/.367, with 22 HRs in 1030 PA. He is not known as S-Rod; indeed, Baseball Reference indicates he is not worthy of a nickname.

Since this was a lefty-righty match up decision, Webster's Dictionary also announced that its next edition would cite this as an example for the word "over-managing".

Kurt Vonnegut and the Burning of Slaughterhouse-Five

If you are either a fan of Kurt Vonnegut or a defender of free speech, you probably will enjoy reading the letter Vonnegut wrote back in 1973 to the head of a North Dakota school board that burnt copies of the classic Slaughterhouse-Five in a school furnace.

(Note: If you are upset that this seems a non-baseball topic, fear not: there is a Yankee angle that I will mention after I am finished venting.)

Here is one of the letter's money quotes (emphasis added):

"It is true that some of the characters speak coarsely. That is because people speak coarsely in real life. Especially soldiers and hardworking men speak coarsely, and even our most sheltered children know that. And we all know, too, that those words really don’t damage children much. They didn’t damage us when we were young. It was evil deeds and lying that hurt us."