Will Bonds Break Hammerin’ Hank’s Record?

It doesn’t take a clairvoyant to prophesize that one of the media events of 2007 is the likely celebration/opprobrium when, or if, Barry Bonds clubs home runs numbers 755 and 756 out of the yard.

But is such a celebration likely to happen? And I’m not musing whether the media will let the historic event slide by without a murmur. No, the question is whether Bonds is physically capable of pummelling the 22 ripsnorters he needs to secure the record.

It wouldn’t be right unless every man and his cocker spaniel speculated on the achievability of this incredible feat, and plenty have done just that. Opinion is divided. Dayn Perry, of Foxsports, thinks Bonds will fall short because of health issues, while the folks at Sports Illustrated believe Bonds will stride ahead of Hammerin’ Hank (on September 7 to be precise).

Me? Until now I have always thought that he’d do it. Why? Well, that’s the problem. I haven’t properly mulled over the what-fors and what-nots, so it is high time I spent some valuable column inches debating the issue.

After a couple of months of contract stalemate Bonds and the Giants have finally inked a $16 million (or have they?), one-year deal, so Bonds now has a green light to attack the record.

What the Projections are Saying

Let’s take a look at what the various forecasts say about Bonds’ chances of circling the bases 22 times. Do they think he will set the record?

             PA      AVG     OBP     SLG      HR      HR/PA    GPA
PECOTA       229     0.267   0.441   0.535    12      5.1%     0.332
CHONE 2.1    376     0.285   0.451   0.557    20      5.3%     0.342
Marcel       452     0.280   0.458   0.560    24      5.3%     0.336
ZiPS         422     0.269   0.464   0.539    21      5.0%     0.344
Bill James   524     0.297   0.495   0.612    32      6.1%     0.376

Crikey, that isn’t especially optimistic. Although there isn’t a clear consensus, the majority are in the NO camp. Only Marcel and Bill James have Bonds securing the necessary round-trippers to pass the Hammer. In fact the James’ forecasts look so hopelessly optimistic compared to the others that it’s quite tempting to ignore them—if he hits like that in 2007 he’ll be back again in 2008 for a crack at 800. The other systems preach conservatism not because they expect a drop-off in production but rather because of a lack of opportunities (plate appearances)—definitely subscribers to the Perry school of thought. James’ numbers aside there is not a massive divergence in home run rate expectation: Marcel and CHONE expect Bonds’ home run rate to remain at its 2006 level, which is a smidgin higher than PECOTA’s and ZiPS’s expectation.

Looking at these numbers the debate boils down to two factors. First, how many plate appearances Barry is likely to register in 2007, and second, what his home run rate will be.

Let’s swivel the lens on to the plate appearance argument.

1. Plate Appearances

Take a look at the yearly breakdown of Bonds’ plate appearances over his career.

Year    Age     PA
1988    23      612
1989    24      674
1990    25      615
1991    26      621
1992    27      605
1993    28      667
1994    29      471
1995    30      631
1996    31      669
1997    32      685
1998    33      690
1999    34      431
2000    35      600
2001    36      662
2002    37      610
2003    38      548
2004    39      614
2005    40      51
2006    41      492

Even into his late 30s Bonds was racking up 600+ plate appearances a year. It was only with his 2005 injury and subsequent convalescence in 2006 that the number dropped. Still, even 492 plate appearances is a healthy total for a 41-year-old slugger—no doubt, he is a very durable fellow. Have a look at how his age-41 season compares with others ranked by plate appearance.

Year    Player      HR      PA
1982    Rose        3       707
1992    Winfield    26      666
2004    Martinez    12      546
1975    Aaron       12      536
1988    Evans       22      522
1985    Nettles     15      512
2001    Ripken Jr.  14      505
2006    Bonds       26      492
1991    Downing     17      473
1961    Musial      15      425
2005    Palmeiro    18      414    

Pretty impressive! Despite gammy knees Bonds comfortably clears the top 10. So, what is the dropoff in plate appearances for these age-41 sluggers as they turn 42? Let’s limit our sample to those players that had at least 150 plate appearances in their age-41 seasons.

         Age 41 PA   Age 42 PA     % Diff
Average  414         331           -20%
Median   396         317           -20%

Although age-decline curves are tricky to apply when hitters approach pensionable age we see that the average dropoff in plate appearances between age-41 and 42 seasons has historically been 20%. Even if we try to manipulate the data and exclude a couple of outliers we arrive at a similar number.

Assuming Bonds sees a 20% attrition in plate appearances, that gives him about 410 opportunities, which means he needs a HR/PA rate of 5.4% to sneak over the Hammer Line, which is marginally above his 2006 pace of 5.3%. If he were to repeat his 2006 long ball rate he’d only need an extra six plate appearances (416) to beat the record. If he were to attain 450 plate appearances, then his home run rate only needs to be 4.9%, which is above what all the projections estimate. One thing is clear: The margin for error in our aging analysis is thin!

One other thing to remember is that Bonds spent zero time on the disabled list last year. True, his usage was carefully managed to avoid aggravating any injury, but it’s worth repeating that Bonds is an incredibly robust individual. Here are his month-by-month plate appearances for 2006:

Month     G       GS      PA
April/Mar.20      17      75
May       23      23      95
June      19      17      69
July      23      21      87
August    24      22      85
Sept./Oct.21      20      82

Obviously as a sportsman in your 40s nothing can be taken for granted, and the projections rightly build in plate appearance regression. I just can’t help but feel that PECOTA and CHONE are overcautious in their estimate. The only way that Bonds will fall short of a 450 plate appearance target is if he hits the DL for a significant period, which is not a racing certainty.

Also don’t forget Bonds has an extra incentive. He wants that record a helluva lot. You can be sure that if he is within sniffing distance he’ll push himself through the pain barrier to get there. In his own mind this is likely to be his last chance.

2. HR Rate

In 2006 Bonds launched 26 home runs in 492 plate appearance for a HR/PA rate of 5.3%, which was a floor he hadn’t seen since his Buccaneer days back in 1991. Then he pumped 25 home runs in 621 plate appearances for a 4.0% HR/PA rate (which back then was nothing to be ashamed about).

Year    Age     HR/PA
1988    23      3.9%
1989    24      2.8%
1990    25      5.4%
1991    26      4.0%
1992    27      5.6%
1993    28      6.9%
1994    29      7.9%
1995    30      5.2%
1996    31      6.3%
1997    32      5.8%
1998    33      5.4%
1999    34      7.9%
2000    35      8.2%
2001    36      11.0%
2002    37      7.5%
2003    38      8.2%
2004    39      7.3%
2005    40      9.8%
2006    41      5.3%

Most of the projections have Bonds’ home run rate at a similar level to what it was in 2006. However, even those who snoozed through last year will recall that Bonds was patchy with the timber. What isn’t clear is how representative his 2006 performance will be of 2007. After coming back from what could have been career-ending knee surgery, he initially looked uncomfortable at the plate. Bonds generates his power through tremendous body torque, which relies heavily on rotation through the knees. Failure of the knee meant that he was no longer able to generate the torque required to launch his usual barrage of power shots. This was particularly evident in the early part of 2006 when his production fell off spectacularly.

Split       G       GS      PA      HR      HR/PA
April/Mar.  20      17      75      3       4.0%
May         23      23      95      4       4.2%
June        19      17      69      4       5.8%
July        23      21      87      3       3.4%
August      24      22      85      5       5.9%
Sept./Oct.  21      20      82      7       8.5%

We see a clear rise in production as the year goes by, which after July culminated in a home run rate comparable to his 2003-2005 seasons. Of course, we must be slightly weary of a two-month sample, but Bonds did report that he was feeling much better in the latter part of the season. Since it is nearly impossible to track down an intelligible Bonds quote, this is what Sporting Green Baseball columnist John Shea said:

“Barry Bonds says he’s overall healthier and especially feels improvement in his legs. He says he feels more swift and fluid when covering ground and chasing down balls in the outfield.”

Given that Bonds has also denied using performance-enhancing drugs despite allegations to the contrary such an assertion from Bonds won’t hold water under the scrutiny of THT Kangaroo court, but it does fit the evidence.

Based on this what is Bonds’ like home run rate in 2007? Again let’s return to our age-41 sluggers to see what happened to performance in the following season (150 minimum plate appearances in each year).

            AGE 41                         AGE 42
Player      PA      HR      HR / PA        PA      HR      HR / PA
Rose        707     3       0.4%           547     0       0.0%
Winfield    666     26      3.9%           592     21      3.5%
Aaron       536     12      2.2%           306     10      3.3%
Nettles     512     15      2.9%           397     16      4.0%
Evans       522     22      4.2%           317     11      3.5%
Downing     473     17      3.6%           390     10      2.6%
Musial      425     15      3.5%           500     19      3.8%
Yastrzemski 408     15      3.7%           387     7       1.8%
Boone       383     5       1.3%           456     1       0.2%
Galarraga   331     9       2.7%           293     12      4.1%
Williams    326     10      3.1%           388     29      7.5%
Fisk        295     19      6.4%           414     13      3.1%
Mays        239     8       3.3%           237     6       2.5%
Dempsey     151     2       1.3%           170     4       2.4%

AVERAGE     427     13      3.1%           385     11      3.0%
MEDIAN      417     14      3.2%           389     11      3.2%

The story here is different to what the plate appearance data tell us. Both the mean and median home run rates barely fall, which indicates that health rather than stamina is the larger barrier to Bonds’ assault on the record books. If we further restrict our sample to those players who clubbed at least 10 home runs in their age-41 season (i.e., aged sluggers), home run production increased slightly in the following year.

What’s apparent is that despite all his troubles, Bonds had a great age-41 season. Only David Winfield has hit more homers. Given his 2006 home run pace after the All-Star Break of 6.3%, it seems as though at a minimum he’ll play well enough to replicate his overall 2006 level; in fact, it wouldn’t be a surprise if he significantly bettered it.

Let’s not get too excited though. Bonds’ run at the record book is almost without precedent. If he hits 22 home runs in 2007 it’ll be one of the greatest age-42 seasons on record. Only one slugger in the history of baseball, the great Ted Williams, has whacked more than 22 home runs at the same juncture in his career.

A Diversion: What May Have Been?

There was some talk immediately after the World Series of Bonds leaving the Giants and moving to another team. Although it’s an academic question now that Bonds has (probably) confirmed his San Francisco deal, it is interesting to see how much difference a switch may have made to Bonds’ odds of being crowned home run king.

AT&T Park is not known as the most porous of yards, so it is fair to assume that Bonds’ production would increase if he moved—actually in 2006 AT&T Park had the lowest home run park factor in the bigs!

Team    Park HR     Bonds HR
ARI     1.06        31
ATL     0.98        28
BAL     1.03        30
BOS     0.94        27
CHA     1.13        33
CHN     1.07        31
CIN     1.08        31
CLE     0.93        27
COL     1.12        32
DET     0.94        27
FLA     0.93        27
HOU     1.05        30
KC      0.93        27
LA      1.04        30
LAA     0.94        27
MIL     1.03        30
MIN     0.95        27
NYA     1.01        29
NYN     0.95        27
OAK     1.00        29
PHI     1.08        31
PIT     0.95        27
SD      0.93        27
SEA     0.96        28
SF      0.90        26
STL     0.97        28
TB      0.98        28
TEX     1.08        31
TOR     1.07        31
WAS     0.94        27

Wow! Had Bonds been plying his trade for the Chicago South Siders, he’d have clubbed an extra seven home runs. Okay, we must be careful of sample size, but the effect is significant in the context of the chase! Also it begs the question of whether Bonds should have moved to a more hitter-friendly environ, perhaps in the American League where he could have contently wallowed in the designated hitter role. However, one reason why Bonds may have been more keen to stay with the Giants is because he is familiar with National League pitchers, and the pitching environment is worse than it is in the AL.

Pulling it all Together

So, what does this all mean for 2007?

Okay, this is pure conjecture, but here are a range of likely scenarios, weighted by my guess of probability. The guesses are based on an assumption that if Bonds remains healthy he is more likely to repeat his second-half 2006 power production, if not then his overall 2006 production is probably more realistic.

Scenario   PA       HR / PA   HR      JB Odds
1          500      6.3%      32      20%
2          400      6.3%      25      20%
3          300      6.3%      19      10%
4          200      6.3%      13      5%
5          500      5.3%      27      5%
6          400      5.3%      21      15%
7          300      5.3%      16      15%
8          200      5.3%      11      10%
AVE        370      5.9%      22

Even with some fairly conservative weightings, you can believe that Bonds will beat Hammerin’ Hanks’ mark. My guess is that Bonds will maintain his health and home run form he showed toward the latter part of 2006. If I had to pick one scenario I’d plump for number two, which means that he’d break the record sometime in late August or early September 2007. My personal view is that there is probably upside in there.

You’ve gotta love a home run chase. Although Bonds’ antics and any attempt at the record will ensure that the spectre of steroids and performace-enhancing drugs are firmly at the fore of public attention, it’ll make for a great soap opera. I, for one, will be glued to the box.

756 here we come.

References & Resources
Thanks to Baseball Reference for the great data it keeps. Also thanks to Patriot whose website I got the HR park factors from.