April 22, 2004

Hank Aaron's Home Cooking

Top Sluggers and Their Home Run Breakdowns

by Jay Jaffe

It's been a couple of weeks since the 30th anniversary of Hank Aaron's historic 715th home run and the accompanying tributes, but Barry Bonds' exploits tend to keep the top of the all-time chart in the news. With homers in seven straight games and counting at this writing, Bonds has blown past Willie Mays at number three like the Say Hey Kid was standing still, which--congratulatory road trip aside--he was, come to think of it.

Baseball Prospectus' Dayn Perry penned an affectionate tribute to Aaron last week. In reviewing Hammerin' Hank's history, he notes that Aaron's superficially declining stats in 1968 (the Year of the Pitcher, not coincidentally) led him to consider retirement, but that historian Lee Allen reminded him of the milestones which lay ahead. Two years later, Aaron became the first black player to cross the 3,000 hit threshold, two months ahead of Mays. By then he was chasing 600 homers and climbing into some rarefied air among the top power hitters of all time.

Aaron produced plenty of late-career homer heroics after 1968. From ages 35 (1969) through 39, he smacked 203 dingers, and he added another 42 in his 40s, meaning that nearly a third of his homers (32.4 percent) came after age 35. The only batters other than Aaron to top 200 homers after 35 are Bonds and Rafael Palmeiro.

As amazing as that late kick is, one thing neither Perry, nor any of the other writers whose Aaron tributes I came across, mentioned is the influence his ballpark may have played on those totals. When examining the effect of parks on any player's career, one should bear in mind the sheer contrast between the comforts of home and the drudgery of travel as well as the venue's specifications and the sample sizes which may affect a single season. Playing at home means getting to sleep in your own bed, and who among us doesn't prefer that to living out of a suitcase?

Nonetheless, the pattern for Aaron is rather convincing. The Braves moved from Milwaukee to Atlanta in 1966. According to Ballparks.com, Milwaukee County Stadium's fences at the time they left were (left to right) 320'- 362'-402'-362'-315', standing at 8'4" to 10' tall. Atlanta-Fulton County Stadium's fences were further back to begin with (325'-385'-402'-385'-325') but they stood only 6' tall. The park underwent some rejiggering in the team's first few years and stood at 330'-375'-400'-375'-330' by 1969. While those dimensions made the field larger than Milwaukee's, the Atlanta stadium's altitude of 1,000 feet above sea level placed it as the highest park in the majors until the Colorado Rockies came along, and its impact on homer totals gave it the nickname "The Launching Pad."

In his nine years in Atlanta, Aaron hit 192 homers at home, 145 on the road. But besides the home runs, the park wasn't especially a hitter's park, at least until a few new NL ballparks came into play midway through that string. Here are Aaron's home-road breakdowns, as taken from the Bill James Historical Abstract (the 1987 version), along with the Batters' Park Factors from Baseball-Reference.com. Remember that the BPFs are for runs and not homers, an important distinction which Perry recently discussed in the context of Dodger Stadium. I've split Aaron's Atlanta period into two eras, one in which his park played as essentially neutral on scoring and the other when it became a hitter's park; the average Park Factors for those eras are weighted by Aaron's plate appearances:

   
Year   PF HHR RHR  PA  PA/HR  Notes 
1966  102  21  23  688  15.6  fences 325-385-402-385-325 
1967   99  23  16  669  17.2 
1968  100  17  12  676  23.3 
1969  100  23  23  639  13.9  fences 330-375-400-375-330
                              add Jarry (Mon), Murphy (SD) 

TOT  100.3 84  74 2672  16.9  

1970  106  23  15  598  15.7  add Three Rivers (Pit), Riverfront (Cin) 
1971  106  31  16  573  12.2  add Veterans (Phi) 
1972  109  19  15  544  16.0 
1973  108  24  16  465  11.6  fences 330-375-402-375-330 
1974  104  11   9  382  19.1  fences 330-385-402-385-330 

TOT 106.7 108  71 2562  14.3   

Aaron's increased homer frequency did coincide with the 1969 change in dimensions; he went from one every 18.2 PA in his first three years in Atlanta to one every 14.2 afterwards. Judging from the BPFs, the stadium's impact on runs was due more to the retirement of Crosley Field (an extreme hitter's park) in favor of Riverfront (a pitcher's park), and the addition of pitcher-friendly Jack Murphy Stadium, the expansion San Diego Padres' park, than to the changed dimensions. A quick scan of various park factors around the league confirms this. Throwing out 1970 because both new stadiums were added mid-season, we see the following Batter Park Factors among the stadiums listed above (weighted to account for the two expansion franchises' late entry):

         
         PIT    CIN    PHI   MON     SD    AVG    ATL
1966-69  99.5  107.8   99.5  100.0  96.0  101.6  100.3
1971-74  97.8   96.5  102.5  103.0  93.5   98.7  106.8 

So Aaron's stadium favored offense. How much did it aid homers? Retrosheet's team splits for the era only go back to 1969, but the data quite clearly shows the "Launching Pad" tag was deserved. From 1969-1974, the Braves and their opponents hit 1.35 homers in Atlanta for every one on the road:

      
      AFCS  Road
1969   161   124  
1970   206   134
1971   186   119
1972   154   125
1973   205   145 (Aaron, Evans & Johnson top 40 HR)
1974   109   108 (league HR rate dropped 21%)

TOT   1021   755
AVG    170   126 

Aaron's rate for that interval is 1.39 home HR for every road HR, slightly above the Braves and their opponents. But among the great home run hitters, how big a deal is all of this? Using the aforementioned Historical Abstract, Retrosheet, and BigLeaguers.com, I compiled the home-road breakdowns of the top 20 home run hitters of all time. Asterisks denote active players, totals are through April 20, and yes, Barry has caused me to update this a few times:

Rk   Player             HR   HHR   RHR
1    Hank Aaron        755   385   370
2    Babe Ruth         714   347   367
3    Barry Bonds*      667   327   340
4    Willie Mays       660   335   325
5    Frank Robinson    586   321   265
6    Mark McGwire      583   285   298
7    Harmon Killebrew  573   291   282
8    Reggie Jackson    563   280   283
9    Mike Schmidt      548   265   283
10   Sammy Sosa*       543   292   251
11   Mickey Mantle     536   266   270
12   Jimmie Foxx       534   299   235
13   Rafael Palmeiro*  529   288   241
14T  Willie McCovey    521   264   257
14T  Ted Williams      521   248   273
16T  Ernie Banks       512   290   222
16T  Eddie Mathews     512   237   275
18   Mel Ott           511   323   188
19   Eddie Murray      504   248   256
20   Lou Gehrig        493   251   242 

As a whole, these men were aided slightly by their parks, hitting 51.4% of their homers at home, an average advantage of 16 homers (292 to 276). Aaron's decisive Atlanta advantage is mostly mitigated by his Milwaukee years, and while he ranks towards the top in his ratio of home HR to road HR, he's still below the group average:

Player   H/R Ratio
Ott       1.718
Banks     1.306
Foxx      1.272
Robinson  1.211
Palmeiro* 1.195
Sosa*     1.163
Aaron     1.041
Gehrig    1.037
Killebrew 1.032
Mays      1.031
McCovey   1.027
Jackson   0.989
Mantle    0.985
Murray    0.969
Bonds*    0.962
McGwire   0.956
Ruth      0.946
Schmidt   0.936
Williams  0.908
Mathews   0.862
Avg       1.058 

Mel Ott took advantage of the Polo Grounds' short foul lines to an almost absurd extreme, while Ernie Banks, Jimmie Foxx, and Frank Robinson also benefited greatly from their home parks. Interestingly enough, lefty-hitting Eddie Mathews, a teammate of Aaron's from 1954-1966, was hurt the most of any of these players; he only played one season in Atlanta and so didn't gain the late-career advantage that Aaron did. One of the bigger surprises on this list was Babe Ruth's home/road breakdown: Despite the "House That Ruth Built" tag applied to Yankee Stadium, he actually had more homers on the road than at home. Here's a quick breakdown of the Bambino's career by phase:

Years    Park    HHR  RHR
1914-19  Fenway   11   38
1920-22  Polo     75   73
1923-34  Yankee  259  252
1935     Braves    2    4
TOT              347  367 

At the outset, I would have wagered that the extreme split in Fenway had more to do with his career on the mound, with the Sox pitching their sensation at home whenever possible to boost attendance and letting him play outfield on the road. But the data to be gleaned from Retrosheet (which doesn't have splits for that era) doesn't support this. Ruth played the outfield for the Sox only in 1918 and 1919, a time during which his homer split, according to James, was nine in Fenway and 31 on the road. At that point his pitching career was on the wane; he made only 34 starts in those two years, compared to 79 in the previous two. Of those 34 starts, only 19 came at Fenway, a minimal advantage. It's more likely that Fenway's righty-favoring dimensions (initially 321'-388'-488'-550' (deepest right center)-402'-314', according to Take Me Out to the Ballpark) really did have an impact on his totals.

In any event, the home/road splits of the top home run hitters make for interesting data. One quick and dirty way of looking at this, or rather two ways, is to double the home totals and the road totals to get numbers approaching their true totals, then comparing them to the current list (whose numbers many of us substitute for sheep in our insomnia-addled hours). The former gives us a number which the hitter might have achieved had he enjoyed all of the advantages of home, while the latter gives us an idea of how he would have fared in more neutral surroundings. Leaving their overall rankings alongside their names to emphasize the shifts, we get:

Rk   Player  2x HHR     Rk   Player  2x RHR
 1   Aaron     770       1   Aaron     740
 2   Ruth      694       2   Ruth      734
 4   Mays      670       3   Bonds*    680
 3   Bonds*    654       4   Mays      650
18   Ott       646       6   McGwire   596
 5   Robinson  642       8   Jackson   566
12   Foxx      598       9   Schmidt   566
10   Sosa*     584       7   Killebrew 564
 7   Killebrew 582      16T  Mathews   550
16T  Banks     580      14T  Williams  546
13   Palmeiro* 576      11   Mantle    540
 6   McGwire   570       5   Robinson  530
 8   Jackson   560      14T  McCovey   514
11   Mantle    532      19   Murray    512
 9   Schmidt   530      10   Sosa*     502
14T  McCovey   528      20   Gehrig    484
20   Gehrig    502      13   Palmeiro* 482
14T  Williams  496      12   Foxx      470
19   Murray    496      16T  Banks     444
16T  Mathews   474      18   Ott       376 

The "home-doubled" list makes for a few dramatic changes. Aaron's advantage on Ruth is increased, but more notably Ott zooms into the top five from the lower reaches of the chart, Frank Robinson crosses the 600 threshold, and Jimmie Foxx reclaims the top-10 status he held a quarter-century ago. Two Chicago Cubs, Sammy Sosa and Ernie Banks, move up considerably in their totals, but then so does the majority of this list. In all, three members of the true top 10 fall out of that elite. The "road doubled" list is much more similar to the actual one in the rankings. Aaron holds only a bare six-homer advantage on Ruth, and Bonds vaults way past his godfather Mays. Only two of the true top 10 fall out, and the jockeying at the top of the list is very minor, with Mathews and Ted Williams both joining its lower reaches. At the bottom of the list, the changes are more dramatic; four members of the 500 HR club fall below that mark with their road-doubled totals, with Ott undercutting 400.

The take-home message of all of this is that while Hank Aaron's homer totals, particularly his late-career surge, were helped by his home park, in the context of the game's top home run hitters the effect is not all that much. For many of the hitters, switching teams or moving into new ballparks tended to balance out their favorable and unfavorable conditions. Taking advantage of one's playing environment isn't a crime, and before we dish out an asterisk for Aaron's tremendous achievement, we ought to also consider that he racked up a good amount of his homer totals in the pitcher-friendly 1960s. Baseball history is full of such fluctuations, and while it's important to consider a player's accomplishments in the context of the terrain, that shouldn't diminish our admiration for Aaron's feat.

That goes for Bonds as well. One fact that's been lost in his homer surge of the past few years is that the Giants' new stadium, SBC Park (formerly Pac Bell) is a terrible home run environment for EBB (Everybody But Barry). Comparing Bonds' home and road HR totals to those of the Giants and their opponents in games at SBC/Pac Bell and elsewhere:

     
      BBH  BBR   SF   RD
2000  25   24   171   206
2001  37   36   146   234
2002  19   27   114   200
2003  23   22   143   173
TOT  104  109   574   813

In the park's first four years, Bonds hit 0.954 homers at home for every one on the road. Think about that--as amazing as his feats have been, his numbers may still be limited by his home park. The Giants and their opponents have suffered even more, hitting only 0.706 homers there for every homer elsewhere. Some might point to darker explanations for Barry's ability to overcome his park, but his achievements deserve some appreciation as well. If he eventually passes Aaron for the top spot, it won't be because of his environment, it will be in spite of it.

The creator of the Futility Infielder Web site, Jay Jaffe is a graphic designer and freelance writer living in New York City. Even in the thin air of Salt Lake City, Jay never hit a Little League home run, and today remains deadlocked with Jason Tyner on the all-time home run list. Jay can be reached at jay@futilityinfielder.com.