[新聞] Projecting career stats is an inexact science
Projecting career stats is an inexact science
By Jayson Stark
ESPN.com
August 4, 2007
Here at ESPN, we're pretty sure we've put Pedro Gomez's face on your TV
screens enough times to alert you to the fact that some guy named Barry
Bonds is about to hit a fairly momentous home run.
Well, it's time to change the subject (at least for the next minute and
a half).
We might want to mention that another man in baseball just hit a home run
that, in its own way, could be considered almost as momentous.
We recognize that a 500th home run doesn't carry the same magnitude as a
755th home run. But if the man hitting it is named Alex Rodriguez, it becomes
a 500th home run of vastly greater significance than just about any of the 21
previous 500th home runs.
Alex Rodriguez hit that 500th home run Saturday, eight days after his 32nd
birthday. Let's try to give you some perspective on what that means.
‧ That's two years and five months younger than Hank Aaron was when he hit
No. 500.
‧ It's two years and four months younger than Willie Mays was when he hit
No. 500.
‧ It's three years and 10 months younger than Mark McGwire was when he hit
No. 500.
‧ And it's four years and eight months younger than Bonds was when he hit
No. 500.
Or think about this another way. A-Rod could blow out his knee, or have
Tommy John surgery, or find some other reason not to play another game until
Labor Day of 2009 -- and still have more home runs than any of those guys
had at the same age.
But since we haven't seen Dr. James Andrews lurking around his locker lately,
we're assuming that won't be happening. So as Barry prepares his 756th-homer
speech, Alex Rodriguez just keeps on making those home run trots.
Another 256 of them, and he and Barry can team up for their own ESPN Classic
Home Run History marathon.
But this is where we need to stop this parade before we start decorating all
the floats. We're amazed by all the people who pretty much assume that it's
now only a matter of time before A-Rod reclaims the record from that
scoundrel, Barry. Well, here's our advice to all of those people:
Heed the powerful lessons of history. Pay attention to the almost
never-ending message the sports world delivers to us every single day.
Which is:
You can't assume anything.
Has A-Rod put himself in perfect position to blow away this record? Of
course. He's younger than guys like Mark DeRosa and Gary Matthews Jr.,
and he's already at 500 homers. But that doesn't necessarily mean he's a
better bet to break Bonds' record than he is to make more money next year
than the entire work force down at 7-11.
For one thing, we can't be sure where Bonds' own total is going to come to
rest. For argument's sake, let's say it's 775. Could be more. Could be fewer.
But let's just use 775 as our guidepost.
That means A-Rod would need another 275 homers to catch him. And for a guy
like A-Rod, hitting 275 home runs probably sounds like it would be an easier
job than editing his wife's T-shirt collection.
But hold on. Let us remind you that 275 home runs is still a mess of homers
-- even in this day and age. It's more than Roger Maris, Steve Garvey, Kirk
Gibson, Brooks Robinson, George Bell and about 400,000 other men hit in their
whole careers, as a matter of fact.
And the other thing we all need to remind ourselves -- always -- is that we
have no idea (none!) how many seasons, how many at-bats, how many
opportunities Alex Rodriguez will get, over the rest of his career, to break
that record.
Maybe he'll keep cranking out big home run years into his late 30s and early
40s, like Aaron and Bonds. But the odds say he won't.
Mays and Mickey Mantle started sliding precipitously at age 36. McGwire was
done at 37.
Jimmie Foxx hit 464 runs before he turned 32. But he was all but washed up by
age 33.
And then there's Junior Griffey.
Could Griffey's career, before age 32, possibly have been more A-Rodesque?
Like A-Rod, Griffey was the No. 1 pick in the draft. Like A-Rod, he started
his career as a teenager in Seattle.
Griffey hit 460 home runs before his 32nd birthday (in 2001). And he would
have been extremely close to A-Rod's total if he hadn't suffered what looked,
at the time, like a freak torn-hamstring injury in spring training of 2001.
Other than an earlier broken wrist, from crashing into a fence, it was the
only serious injury of Griffey's career to that point.
But then, just as we were all about halfway through our big
Why-Junior-Will-Pass-Hank term papers, you know what happened:
Griffey turned into a walking HMO ad.
Maybe that will happen to A-Rod. Maybe it won't. But not even
baseballpsychic.com can tell you that answer. That part is up to the
baseball gods.
So all we can do is look to the past for guidance. And that's what we did.
We studied what happens to the great sluggers after they blow out the candles
on their 32nd birthday cake. The results are fascinating:
‧ Of the top 10 names on the all-time homer list, seven of them had a season
that produced the best home run ratios of their careers after they turned
32. So that's good.
‧ But only three of them (Aaron, Bonds and Rafael Palmeiro) had that season
in their late 30s. So that's bad.
‧ And if you think it's so easy to hit 275 home runs at this stage of a
career, consider this: Only six players in history have ever done it --
Bonds, Aaron, Ruth, Mays, McGwire and Palmeiro. And there are, shall we
say, serious performance-enhancement questions about half of that group.
‧ You may also notice that every one of those guys was an outfielder, a
first baseman or a DH. None was a third baseman. And none was a
shortstop -- which could be relevant, since A-Rod has made noises about
returning to his old position if he leaves the Yankees. The only third
baseman who ever got within 50 homers of hitting 276 after turning 32 was
Mike Schmidt (237). No shortstop ever hit more than 100 homers after
turning 32. (Eddie Joost hit 100 on the nose.) And Cal Ripken hit 162
while dividing his time between short and third.
So what does all this say about Rodriguez's chances of passing Barry?
One man who is bullish on those chances is David Vincent, the legendary SABR
home run historian. Despite the lack of precedent for any third baseman or
shortstop hitting this many home runs at this stage of his career, Vincent
thinks A-Rod's position actually gives him an advantage over someone like
Griffey.
"A-Rod plays a position now that will take less of a toll on his body than
center field," Vincent said. "He does not routinely run into walls or dive
for balls like Junior. I think he will be healthier, which could enable him
to play longer at a top level."
A-Rod has averaged 46 homers a year over the 10 full seasons in his career
(not even counting this year). So Vincent finds it easy to envision him
averaging 35 a year for the next eight seasons -- which would get him to
780 or so.
But that always seems easy to envision when a player is in the prime of his
career. Our question is whether that's a mathematically- or historically-safe
assumption.
For that answer, we turned to Dan Heisman, a sabermetrician who for years has
used variations on Bill James' Favorite Toy formula to analyze active players'
odds of achieving certain milestones. Here is what he found:
‧ Using projections for this year's totals, he calculated that A-Rod has a
48 percent chance of hitting 775 homers (or 52 percent of hitting 756).
‧ The only other hitters who even had better than a 15 percent chance at
775 were Albert Pujols (26 percent), Ryan Howard (18 percent) and Adam
Dunn (also 18).
So obviously, A-Rod has put himself in by far the best position of any other
active player. But even that 48 percent calculation tells you he's still a
stronger bet not to catch Bonds than to catch him.
And remember, as recently as 2000, when Griffey had 438 homers at age 30,
he was rated as having a 42 percent chance to hit 756, and a 38 percent
chance to hit 775. But by the time Griffey arrived at No. 500 -- four years
and an assortment of major injuries later -- his chances had decreased
slightly.
Like to zero.
So just for fun, we asked Heisman if he could also calculate what the chances
looked like for the next youngest 500-homer men -- Aaron, Ruth, Mays,
Sammy Sosa and Foxx -- at the time they hit their 500th.
Sosa turned out to be the guy who topped them all, at 39 percent (and a
44 percent chance of reaching 756). Ruth was next at 29 percent (35 percent
for 756), Foxx at 24 (29 for 756) and Mays at 22 (27 for 756).
But wait. What about the guy who wound up as the actual record-holder, Aaron?
You'll be either stunned or amused to learn that he projected to a zero
percent chance back then at either 756 or 775 (because he'd slumped to only
29 homers the year he hit his 500th).
And that tells you all you need to know about the dangers of getting into the
projection business -- or the assumption business -- on stuff like this. It's
a reminder that the chances often look great of all kinds of records falling
-- until they don't.
So as A-Rod celebrates No. 500, feel free to applaud the feat and savor the
moment. Then it'll be time to kick off this very argument at a tavern near
you.
Why do we have a feeling we'll still be kicking at it in the year 2013?
http://sports.espn.go.com/mlb/columns/story?columnist=stark_jayson&id=2947658
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