Where does Verlander Rank Among Tigers ERA+ Leaders?

In the previous post, the ERA+ statistic was defined and its interpretation clarified.  In this post, it will be used to rank the top Tigers pitchers of all time.  I believe I did something similar on this blog a few years ago, but that was before current ace Justin Verlander had enough innings to qualify and before he had his elite 2011 season. The table below lists the top 15 Detroit hurlers of all time, only including their years with the Tigers.

The first six columns of the table should be self explanatory.  If you read the previous ERA+ post linked above, you might remember that the interpretation of ERA+ is a bit tricky.  So, I've added another column to the table (%) which tells us how far below the league average the pitcher's ERA fell.  For example, Hall-of-Famer southpaw Hal Newhouser had a career ERA+ of 130 which which means his ERA was 23% better than the average pitcher over the course of his career.  In order to qualify, a pitcher needs 150 career starts.

Table 1: All-time Tigers ERA+ Leaders

Player	From	To	IP	ERA	ERA+	%
Hal Newhouser	1939	1953	2,944	3.07	130	23
Tommy Bridges	1930	1946	2,826	3.57	126	21
Dizzy Trout	1939	1952	2,591	3.20	125	20
Justin Verlander	2005	2011	1,315	3.54	124	19
Frank Lary	1954	1964	2,008	3.46	116	14
Jim Bunning	1955	1963	1,867	3.45	116	14
Schoolboy Rowe	1933	1942	1,445	4.01	114	12
Virgil Trucks	1941	1956	1,800	3.50	114	12
Fred Hutchinson	1939	1953	1,464	3.73	113	12
Denny McLain	1963	1970	1,593	3.13	110	9
Ed Killian	1904	1910	1,536	2.38	110	9
Bill Donovan	1903	1918	2,137	2.49	109	8
Jack Morris	1977	1990	3,042	3.73	108	7
Dan Petry	1979	1991	1,843	3.84	105	5
Mickey Lolich	1963	1975	3,361	3.45	105	5

Data source: Baseball-Reference.com

In his seven seasons with the Tigers. Verlander has an ERA+ of 124 which makes him 19% better than average.  He ranks fourth all time behind Newhouser, Tommy Bridges and Dizzy Trout.  Verlander's total includes his 2008 season where he had an ERA+ of 93.  In each of his other
seasons, he had ERA+ of at least 124.  We can't very well throw out his worst season, but he certainly has an excellent chance to raise his ERA+ in the future. 

One thing you might notice on the chart is that Jack Morris falls slightly below Denny McLain and Ed Killian in ERA+, but pitched almost twice as many innings.  So, Morris was very close to McLain and Killian in quality, but does not get credit for his much larger workload.  That is because ERA+ measures quality only and not quantity.  There are other measures which combine quality and quantity which will be covered later.

What is ERA+?

I often use the statistic Adjusted Earned Run Average (ERA+) in my posts about baseball history.  I believe many readers of this blog have a general idea of what ERA+ means and why it is useful in historical comparisons.  However, I have seen it misinterpreted in several places around the internet, so I'm going to try to clear up any confusion here.

I'll start with an example of how the ERA+ measure can be useful.  Back in 1906, St. Louis Cardinals hurler Buster Brown had a 2.64 ERA finishing 21st in the National League.  Nearly a century later in 1998, the legendary Roger Clemens led the American League with a 2.65 ERA pitching for the Toronto Blue Jays.  So, we have two pitchers with almost identical ERAs but Clemens actually had a much better season than Brown. 

How can two pitchers with essentially the same ERA have such dissimilar rankings in their leagues?  The reason is the vastly different contexts in which they played.  Brown pitched at the height of the Deadball Era while Clemens pitched in the high-powered run scoring environment of the late 1990s.  In 1906, the league ERA was 2.62 and, in 1998, it was more than two runs higher at 4.65.  

Since ERA doesn't always do a good job of comparing the quality of pitchers across eras, many analysts like to use ERA+ which adjusts for the league average ERA and the home park of the pitcher.  In general, an ERA+ of 100 means that a pitcher had an average ERA relative to his league, an ERA+ of more than 100 indicates that he was better than average and an ERA+ of less than 100 indicates worse than average.

Brown's 99 ERA+ in 1906 says than he was very close to average while While Clemens 176 ERA+ tells us that he was far above average.  One can find the ERA+ statistic for any pitcher in any season at Baseball-Reference.com.

The specific interpretation of ERA+ is where some people get confused.  There is a common misconception that an ERA+ of 176 means that Clemens was 76% better than league average.  What it really means is that the league average was 76% worse than Clemens.  It sounds like the same thing, but it's really not.

In order to see how Clemens performed relative to the league average, it is necessary to take the reciprocal of ERA+ and then subtract from 100.  The reciprocal of 176 is (100/176)=0.57 or 57%.  So Clemens was 100-57= 43% better than league average after adjusting for league and ballpark.  So, that's how we interpret ERA+.  If that's enough for you, then stop here.  If you want to see a detailed calculation then read on.

Detailed Calculation of ERA+
 
ERA+ involves a two-step formula with league-adjusted ERA (Lg Adj ERA) calculated first:

Lg Adj ERA = (Lg ERA/Pitcher ERA) x 100

ERA+ = (Lg Adj ERA + Lg Adj ERA x PF)/2

where PF = Park Factor = the amount by which a ballpark inflates or deflates the ERA of a typical pitcher.

Let's use Jake Peavy's 2007 season with the Padres as an example:

ERA = 2.54

Lg ERA = 4.43

PF for Runs = 0.80 for Petco Park

Lg Adj ERA = (4.43/2.54) x 100 = 174

ERA+ = (174 + 174 x 0.80)/2 = 157
   

Tigers Rotations of 1940s were Best

Two-time MVP award winner Prince Hal Newhouser anchored several Tigers staffs in the 1940s.  (Photo courtesy of Baseball Hall of Fame and Examiner.com)

In an earlier post, I looked at the best rotations in the history of baseball according to the Baseball-Reference Wins Above Replacement (WAR) statistic.  In order for a rotation to qualify, it needed four starting pitchers with at least 20 starts, 162 innings and two WAR.  The 1946 Tigers rotation of Hal Newhouser, Dizzy Trout, Virgil Trucks and Fred Hutchinson finished second in total WAR trailing only the 1912 Red Sox.

Now, I will concentrate on just the Tigers staffs. Only ten Detroit rotations met the  above qualifying criteria, so the WAR cut-off will be relaxed from two to one.  The top 12 rotations are listed in the table below.

Title 1: Tigers Top Pitching Rotations by WAR, 1901-2011

Year	Team	Pitcher 1	WAR	Pitcher 2	WAR	Pitcher 3	WAR	Pitcher 4	WAR	Total
1946	DET	Hal Newhouser	9.0	Dizzy Trout	7.2	Virgil Trucks	3.9	Fred Hutchinson	3.8	23.9
1949	DET	Virgil Trucks	7.2	Hal Newhouser	5.9	Fred Hutchinson	4.4	Ted Gray	3.5	21.0
1907	DET	Ed Killian	5.8	Ed Siever	5.2	Bill Donovan	4.2	George Mullin	2.4	17.6
1957	DET	Jim Bunning	6.1	Paul Foytack	4.1	Billy Hoeft	3.5	Duke Maas	2.9	16.6
1950	DET	Art Houtteman	6.6	Dizzy Trout	3.6	Fred Hutchinson	3.3	Hal Newhouser	3.0	16.5
1933	DET	Firpo Marberry	5.0	Tommy Bridges	4.3	Vic Sorrell	3.3	Carl Fischer	2.6	15.2
1948	DET	Hal Newhouser	6.3	Virgil Trucks	3.7	Dizzy Trout	3.0	Fred Hutchinson	2.2	15.2
1942	DET	Hal White	4.4	Al Benton	4.2	Tommy Bridges	3.3	Virgil Trucks	3.2	15.1
1962	DET	Hank Aguirre	6.9	Jim Bunning	4.3	Don Mossi	1.5	Phil Regan	1.1	13.8
1943	DET	Dizzy Trout	4.6	Tommy Bridges	4.4	Virgil Trucks	3.3	Hal Newhouser	1.2	13.5
2006	DET	Justin Verlander	3.7	Nate Robertson	3.4	Jeremy Bonderman	3.2	Kenny Rogers	3.0	13.3
1935	DET	Schoolboy Rowe	4.3	Tommy Bridges	3.4	Elden Auker	3.0	General Crowder	1.6	12.3

The table reveals that the 1940s was the ultimate pitching decade for the Tigers.  If we include the 1950 season, six of the top ten staffs came from that one narrow time period.  The 1940s pitchers showing up most often are the left-handed Newhouser and right-handed Hutchinson, Tout and Trucks, each appearing at least four times.  Tommy Bridges also made the list four times spanning the 1930s and 1940s.   

The best four-man WAR totals came in 1946 (23.9) and 1949 (21.0) but the deepest staff was the 1942 sextet of Bridges, Newhouser, Trout, Trucks, Al Benton and Hal White.  All six of those pitchers had 20+ starts, 162+ innings, 2+ WAR and 115+ ERA+.  No other staff in baseball history has had that many pitchers reaching that impressive combination.

The most recent rotation on the list was the 2006 group of Justin Verlander, Nate Robertson, Jeremy Bonderman and Kenny Rogers.  That staff did not have a dominant pitcher, but each of the four accumulated at least three WAR.  It's a little surprising that none of the 1980s staffs made the cut.  The best 1980s rotation by the stated criteria was the 1980 staff of Dan Schatzeder, Jack Morris, Dan Petry and Milt Wilcox finishing 19th with just 9.4 WAR.

The current staff of Verlander, Doug Fister, Max Scherzer and Rick Porcello has the potential to crack the top dozen in the next year or two, but it's not easy to have four pitchers all be successful and stay healthy at the same time.  It's happened just once in the last fifty Tigers seasons.

PECOTA Sees Tigers Offense as Two-Man Show

Baseball Prospectus recently released its Player Empirical Comparison and Optimization Test Algorithm (PECOTA) projections for 2012.  PECOTA is a complicated projection system created by Nate Silver and recently improved by Colin Wyers.  It uses the statistics and characteristics (age, height, weight, position) of a given player and the statistics and characteristics of similar players to arrive at projections for that player.

Accessing the data requires a subscription, so I can't reveal too much, but I can tell you that PECOTA views the Tigers offense as the Miguel Cabrera and Prince Fielder show.  It projects that both will have OPSs north of .920 and that they will finish second and third in Major League Baseball behind new Angels slugger Albert Pujols.  It is also forecasting 37 homers for Fielder, which would tie him for the lead with Pujols. 

Beyond Cabrera and Fielder, PECOTA does not project any Tiger to have an OPS above .800.  Who will have the third highest OPS on the Tigers?  Alex Avila? Brennan Boesch? Jhonny Peralta? No, PECOTA projects that second baseman/outfielder Ryan Raburn will finish third with a .773 OPS.

The system also decides which players are most likely to improve.  It says that outfielders Austin Jackson and Andy Dirks have the best chance among current Tigers of improving, although it is not actually projecting that to happen in 2012.  The most comparable player to Jackson is former Reds out fielder Bobby Tolan.  Dirks is most comparable to Paul Blair and Amos Otis (that would be nice!) 

If you subscribe to Baseball Prospectus, you can download your copy of projections for all players.