Baseball Player Won-Loss Records
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Comparing Positions

Player Won-Lost Records are an excellent overall measure of player value. When context and the effects of teammates are controlled for, Player Won-Lost records can also, in my opinion, serve as an excellent starting point for measuring player talent. As a means of comparing players who play different positions, however, raw Player Won-Lost records are not really an ideal comparative tool.

In constructing Player Won-Lost records, all events are measured against expected, or average, results across the event. Because of this, fielding Player Won-Lost records are constructed such that aggregate winning percentages are 0.500 for all fielding positions. Hence, one can say that a shortstop with a defensive winning percentage of 0.475 was a below-average defensive shortstop and a first baseman with a defensive winning percentage of 0.510 was an above-average defensive first baseman, but there is no basis for determining which of these two players was a better fielder – the below-average fielder at the more difficult position or the above-average fielder at the easier position.

From an offensive perspective, batting Player Won-Lost records are constructed by comparing across all batters, not simply batters who share the same fielding position. In the National League, this means that offensive comparisons include pitcher hitting, so that, on average, non-pitcher hitters will be slightly above average in the National League, while, of course, because of the DH rule, the average non-pitcher hitter will define the average in the American League.

These are, in fact, two sides of the same coin. There is a nearly perfect negative correlation between the average offensive production at a defensive position and the importance and/or difficulty associated with playing that position. That is, players at the toughest defensive positions tend to be weaker hitters than players at easier defensive positions.

Bill James used this observation to define what he called the Defensive Spectrum:

1B    –   LF   –   RF   –   3B   –   CF   –   2B   –   SS   –   C

Positions get more difficult/valuable defensively moving left to right (e.g., shortstop is a more defensive position than second base) while offensive production increases moving right to left (e.g., first basemen out-hit left fielders).

When comparing, for example, a left fielder to a shortstop, one has to somehow balance the fact that left fielders are expected to hit better than shortstops against the fact that shortstops are, on average, better defensive players than left fielders.

There are three ways to do this:

(1) One can adjust offensive Player Won-Lost records based on the defensive position of the player,

(2) One can adjust defensive Player Won-Lost records based on the defensive position of the player, or

(3) One can adjust the baseline against which players are measured.
I believe that the best choice is (3), measuring players against different baselines based on the position(s) which they played.

Positional Averages
The table below shows (context-neutral) Player Won-Lost records based on the defensive position of the player for every season for which I have estimated Player won-lost records. Offensive Player Won-Lost records are shown first, followed by overall records. Results here distinguish between DH leagues (the American League since 1973) and non-DH Leagues.

Context-Neutral Player Won-Lost Records by Defensive Position
(Offensive Player Decisions)

DH Leagues Non-DH Leagues
Position Wins Losses Win Pct. Wins Losses Win Pct.
Pinch Hitter 1,291.21,422.00.4764,676.25,195.10.474
Pitcher 2.35.40.2965,217.910,005.30.343
Catcher 6,484.37,038.40.48013,602.914,126.90.491
First Base 7,980.27,311.00.52216,598.714,666.10.531
Second Base 7,192.77,638.50.48514,902.615,337.40.493
Third Base 7,344.27,386.10.49915,574.814,863.70.512
Shortstop 6,739.17,404.10.47613,944.715,000.10.482
Left Field 7,880.17,563.70.51016,736.314,918.50.529
Center Field 7,866.27,772.30.50316,433.715,287.60.518
Right Field 7,852.97,411.90.51416,617.914,900.70.527
Designated Hitter 7,502.87,180.10.5113.52.70.563
Pinch Runner 154.5157.00.496257.3262.50.495
All Non-P Fielders 59,339.759,526.00.499124,411.6119,100.90.511


Context-Neutral Player Won-Lost Records by Defensive Position
(Total Player Decisions)

DH Leagues Non-DH Leagues
Position Wins Losses Win Pct. Wins Losses Win Pct.
Pinch Hitter 1,291.21,422.00.4764,676.25,195.10.474
Pitcher 45,038.545,081.70.50093,430.898,293.90.487
Catcher 7,701.08,257.00.48316,165.016,693.40.492
First Base 9,536.58,870.30.51819,615.917,684.70.526
Second Base 10,351.110,783.20.49021,077.621,485.40.495
Third Base 10,172.010,216.00.49921,101.120,400.50.508
Shortstop 10,171.810,825.70.48420,809.921,846.50.488
Left Field 11,768.911,444.80.50724,412.722,583.20.519
Center Field 11,258.711,158.90.50223,394.722,232.60.513
Right Field 11,634.111,184.20.51024,188.422,452.60.519
Designated Hitter 7,502.87,180.10.5113.52.70.563
Pinch Runner 154.5157.00.496257.3262.50.495
All Non-P Fielders 82,594.082,740.10.500170,765.2165,378.80.508


A few comments:

(1)    Non-pitchers have an offensive winning percentage about 1.2% higher in the National League than in the American League,

(2)    Designated hitters are above-average hitters, but are comparable hitters to corner outfielders and are slightly worse hitters, on average, than first basemen,

(3)    Pinch hitters are, on average, worse hitters than any other position (other than pitcher, of course).

Positional Averages for Non-Pitchers
Comparisons of this nature are based on an implicit expectation that an average player at every position is equally valuable. Over a long enough time period, such as the 60+ years of the "Retrosheet Era", offensive winning percentages tend to follow the defensive spectrum fairly closely, suggesting that such an assumption is probably at least generally reasonable. For specific leagues in specific seasons, however, there may be exceptions. In the 1999 American League, for example, 3 of the 14 teams’ shortstops were Derek Jeter (who batted .349/.438/.552 in 739 plate appearances), Nomar Garciaparra (.357/.418/.603 in 595 PAs), and Alex Rodriguez (.285/.357/.586 in 572 PAs). That same season, the AL Silver Slugger for third basemen went to Dean Palmer, who batted .263/.339/.518 for Detroit. For that particular league-season, AL shortstops actually out-performed AL third basemen in offensive win percentage, 0.4868 - 0.4867. It is perfectly reasonable to think that AL shortstops as a group were “above-average” in the 1999 American League. Centerfielders - led by Willie Mays, Duke Snider, Larry Doby, et al., also outhit corner outfielders in several years of the 1950s.

One way to ameliorate this problem is to combine the two leagues – American and National – so that individual performances are less important (e.g., 3 shortstops represent only 10% of all starting shortstops in the major leagues as a whole). Before doing this, however, one has to adjust National League non-pitchers’ offensive winning percentages to account for the lack of a DH in these leagues. This produces the following offensive winning percentages:

Context-Neutral Player Won-Lost Records by Defensive Position

Major-League wide: DH-Adjusted
Position Wins Losses Win Pct.
Catcher 19,807.021,445.50.480
First Base 24,237.222,318.90.521
Second Base 21,788.523,282.70.483
Third Base 22,598.122,570.60.500
Shortstop 20,396.822,691.20.473
Left Field 24,271.522,827.00.515
Center Field 23,961.523,398.30.506
Right Field 24,128.522,654.90.516


Ranking them from highest winning percentage to lowest produces the following “defensive spectrum”:

1B    –    RF    –    LF    –    CF    –    3B    –    2B    –    C    –    SS


This is extremely close to Bill James’s defensive spectrum. Third basemen and center fielders are reversed, although the basic conclusion one can draw here is that third basemen and center fielders are both basically average hitters. Shortstops and catchers are also slightly reversed, although, again, the broad conclusion is simply that both positions are populated by relatively poor hitters through major-league history.

Another way to think about these results is to figure out what defensive winning percentage would be needed for each position to have a cumulative 0.500 winning percentage. This is done below.

Implied Defensive Won-Lost Records

Major-League wide: DH-Adjusted
Position Wins Losses Win Pct.
Catcher 4,601.22,962.70.608
First Base 3,616.55,534.80.395
Second Base 10,060.18,566.00.540
Third Base 8,346.68,374.10.499
Shortstop 11,430.19,135.60.556
Left Field 10,833.312,277.80.469
Center Field 10,060.910,624.20.486
Right Field 10,601.212,074.80.468


Another way to compare defensive positions is to look at players who played multiple defensive positions and compare their fielding records across positions. This is done in a separate article.

Pitchers
As a general rule, pitchers tend to perform better – lower ERA, more strikeouts, better context-neutral winning percentage – as relief pitchers than as starters. This can be measured in two ways.

First, one can compare the average winning percentage for starting pitchers and relief pitchers. Over the time period for which I have estimated Player won-lost records, starting pitchers compiled an average winning percentage of 0.499, while relief pitchers amassed a 0.502 winning percentage. From this, one could conclude that the positional average for starting pitchers is about 0.003 lower than for relief pitchers.

Such a conclusion would assume, however, that an average starting pitcher is equal in value to an average relief pitcher (on a per-inning basis). This may not be a reasonable assumption. In general, starting pitchers tend to be better pitchers than relief pitchers, particularly than non-closers.

Alternately, one can look at individual pitchers who both started and relieved in the same season. Over the seasons for which I constructed Player won-lost records, a total of 12,970 player-seasons included both starting pitching and relief pitching. Weighting each of these players’ performances by the harmonic mean of their starting and relief pitching Player Decisions, these pitchers compiled a weighted average winning percentage of 0.474 as starting pitchers and 0.497 as relief pitchers. Using the Matchup Formula to re-center these winning percentages around 0.500, the average winning percentage for these pitchers as starters was 0.492 and for these pitchers as relievers was 0.518. Looked at in this way, the positional average for starting pitchers appears to be about 0.025 lower than for relief pitchers.

For my work, I use this latter difference. That is, the positional average for starting pitchers is set about 0.025 lower than the positional average for relief pitchers. Because this gap is wider than the observed gap in the cumulative winning percentage for all starting pitchers vis-à-vis all relief pitchers, the result of this is that starting pitchers are, on average, slightly above-average pitchers, while relief pitchers are, on average, slightly below-average pitchers. I believe that this fairly represents the reality of how pitchers are used in Major-League Baseball.

Positional Averages for Individual Players
Unique positional averages by position are calculated by season. A positional average winning percentage is then constructed for each individual player based on the positions at which the player accumulated his wins and losses. This is done as follows.

1.    Offensive Player Decisions
For offensive player games (wins plus losses), the positional average is the average (DH-adjusted) offensive winning percentage for that position for that season. For games played under NL rules, then, a “pitcher hitting penalty” is added to the positional average. This is equal to the difference in the average winning percentage of non-pitcher position players (i.e., excluding pinch hitters, pinch runners, and designated hitters) in NL games versus the average winning percentage of these players in AL games. As the table above shows, the “pitcher hitting penalty” has been just over 1% on average. The specific penalty used in this calculation is uniquely calculated each year.

For players who accumulated offensive player decisions while playing multiple defensive positions (where, for lack of a better term, I include “pinch hitter”, “pinch runner”, and “designated hitter” as unique “defensive positions”) or who played some games under AL rules and some games under NL rules (so that the “pitcher hitting penalty” is only applied to some of his player decisions), the overall offensive positional average is simply equal to the weighted average of the unique positional averages across positions and across leagues, weighted by the number of player decisions accumulated by position and league.

2.    Pitching Player Decisions
For pitchers, unique positional averages are calculated for starting pitchers and relief pitchers. These averages are calculated by year (with both leagues combined, with no DH-adjustments since an average pitcher is a 0.500 pitcher in both leagues by definition) by looking at pitchers who started and relieved in the same season (for the same team) and comparing average winning percentages of these pitchers as starters and as relievers. These average winning percentages are adjusted to an average 0.500 winning percentage using the Matchup Formula. As noted above, on average, the Positional Average for starting pitchers is around 0.492, while for relievers the Positional Average for relief pitchers is around 0.518. These averages vary, however, by year.

3.    Fielding Player Decisions
By construction, cumulative fielding winning percentage will be 0.500 for every defensive position in every league every year. Hence, the Positional Average for fielding player decisions is 0.500 for all players.

Overall Positional Average
The overall Positional Average for a player is then simply a weighted average of his offensive, pitching, and fielding averages where the weights used are the relative offensive, pitching, and fielding decisions compiled by the player.

These Positional Averages form the basis for comparing players across positions, either by comparing players to “average” or to “replacement level”. Positional averages by position by season are shown here.


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