CSS Button No Image Css3Menu.com

Baseball Prospectus home
Click here to log in Click here for forgotten password Click here to subscribe

<< Previous Article
Premium Article Pebble Hunting: Soundi... (03/14)
Next Article >>
Fantasy Article Five to Watch: America... (03/17)

March 14, 2014

Attrition By Position

How Long Do Players at Each Position Last?

by Robert Arthur

Like many baseball fans, I was taken aback by Derek Jeter’s declaration of his impending retirement. Together with Roy Halladay’s somewhat quieter conference and Mariano Rivera’s farewell tour, a trio of players I admired tremendously will soon be out of baseball. It’s a bittersweet fact of the big leagues that just as one generation of transcendent superstars is born (e.g. Mike Trout, Bryce Harper), another trails off gently into retirement.

The question of career length has more than emotional import within the business of baseball. Owing to the advanced age at which many players are hitting the market, for many free agent contracts there is substantial risk that a player’s useful career will end before his deal does. Even when a player does remain employed late into his 30s, between injuries and the tireless decline of aging, the terminal years of his career can be unproductive.

We usually view the question of when a given player’s career will end as largely unforeseeable. One twisted swing of the bat or one wrong pitch can cause catastrophic, career-destroying damage. After Halladay’s magnificent 2011 (arguably the best season of his illustrious career), and his relatively healthy history to that point, who could have foreseen that a string of seemingly innocuous strains would bring about the end of his career?

Because of the randomness of injuries and the overarching shadow of survivor bias, studying career length is a statistically thorny issue. To overcome these obstacles, I’ll employ a special type of regression model called a Cox Proportional Hazards Model. This kind of model was built specifically to estimate how survival varies as a function of different medical treatments; it’s the kind of tool medical researchers use to understand whether patients on a drug live longer than those given a placebo. The analysis is therefore somewhat macabre, if also (and more importantly) technically accurate.

Indicators and Myths
The first factor I wanted to investigate was how career lengths might differ depending on the dominant position a player fielded. I was inspired to look into this by the collection of heuristics on the subject I have seen repeated in baseball circles: that second basemen and catchers fall off in their early 30s, and that first basemen last longer.

Some methodology, should you be interested or wish to confirm my results: I used Sean Lahman’s player database to extract career lengths for more than 10,000 players, and I limited my sample to careers beginning post-1900. I linked these records to fielding data and extracted the position at which a player had logged the most innings as his dominant position. Then I fit the survival model.

The rest of this article is restricted to Baseball Prospectus Subscribers.

Not a subscriber?

Click here for more information on Baseball Prospectus subscriptions or use the buttons to the right to subscribe and get access to the best baseball content on the web.

Cancel anytime.

That's a 33% savings over the monthly price!

That's a 33% savings over the monthly price!

Already a subscriber? Click here and use the blue login bar to log in.

Related Content:  Aging,  Attrition,  Career Length

16 comments have been left for this article. (Click to hide comments)

BP Comment Quick Links


Interesting read. I find it interesting that second basemen top the list of position players (i.e. not DHs) but it isn't surprising. Most second basemen have already been converted from other positions due to a lack of skills (lack of range or arm to play SS or 3B). The majority of 2b also don't have the stick to be useful at other positions like 1b or the OF if their skills diminish further with age. Once they lack the skills to play second, where do they go?

Cano is interesting in that he, like Hornsby (or heck, further down the list, even a guy like Jeff Kent), is a tremendous hitter. He has enough bat to be very useful as a 1b or corner outfield over the long haul. That gives him another place lower on the defensive spectrum in which he can move.

Do I agree with you that his contract is risky? Absolutely. However, much of his value is tied to his bat; one that could certainly suffice at less defensively-challenging positions. That might make him a strong candidate to be an outlier in this instance.

Mar 14, 2014 05:20 AM
rating: 13

This seems to make intuitive sense. There are more players to choose from at the lower end of the spectrum, so players are shuffled out as soon as they decline.

Look at players such at Brendan Ryan and Clint Barmes. They can't hit and haven't for years, but it's hard to find a good shortstop so they linger in the league. The minute a guy like Richie Sexson stops hitting, it's a short path to forced retirement.

Mar 14, 2014 05:53 AM
rating: 4

Of course, the moment Brendan Ryan can't flash awesome leather, he's toast too.

Which raises a point. It is tempting to speculate that for any position except pitcher (and DH, to the extent that it is a "position" rather than the absence of one), having a diverse tool set protects a player from premature retirement, by allowing the player to step up his game in one area, at least in principle, when it declines in another one. It isn't so simple, of course; having one's defense tool go from 70 to 40 due to weight gain, let alone injury, doesn't mean that a corresponding increase in the hit tool will occur or is even possible. But -- I speculate -- players who can make those tradeoffs work will have a better sense of a long career. They can't do that if they only have the one tool to begin with, no matter how outstanding it is.

What does this have to do with Cano? Dunno, but he does strike me as a multi-tool kind of player, unlike some of the guys who are given inexplicably long contracts when in or leaving their prime.

Mar 14, 2014 07:37 AM
rating: 1

"Of course, the moment Brendan Ryan can't flash awesome leather, he's toast too."

Except that the stats determining whether Ryan is "flashing awesome leather" are much murkier than the ones determining his offensive value, and thus some players can stick around based on their reputation rather than performance.

Also, you skipped over the other part of marshaja's point. There are fewer players who are considered quality defenders at the toughest positions; thus, even if Ryan ceases to flash said awesome leather, the club stuck with him at the end of his utility might not have anyone better ready to step in.

Mar 15, 2014 14:53 PM
rating: 1

You're missing the point. Once Ryan can't flash the leather (and while the quality of his defense may be a "murkier" subject for sabermetricians than offense, managers and GMs have definite opinions about it), any near-replacement-level shortstop is a possible replacement for him. Better-than-average defensive shortstops who absolutely cannot hit aren't that hard to find. There will be someone "ready to step in" rather than pay major-league salaries to a guy with a .563 OPS. Once Ryan's defensive skills deteriorate to merely better than average, rather than elite, I repeat: he's toast.

Mar 15, 2014 20:55 PM
rating: 1
Matt Trueblood

While it measures something slightly different, this seems to accord with Nate Silver's findings of eight years ago:


Interesting stuff, Robert.

Mar 14, 2014 07:05 AM
rating: 3
BP staff member Robert Arthur
BP staff

That piece is one of my all-time favorite articles on the subject.

Mar 14, 2014 08:00 AM

I'd be very interested to see the impact Tommy John surgery has made on the pitcher end over the past 40 years.

Very interesting article.

Mar 14, 2014 07:20 AM
rating: 1
BP staff member Robert Arthur
BP staff

There is indeed a significant trend over time, that'll be in the next piece on this subject (hopefully).

Mar 14, 2014 08:02 AM

I was thinking exactly the same thing... can't wait to see the follow-up piece, Robert.

Mar 15, 2014 14:55 PM
rating: 0

It would be interesting to include the impact on plate appearances or WAR as well-- for example, many of the catchers "survive" (still are on MLB teams), but regress to backup roles with reduced playing time, salary, etc. Or they spend half the season on the DL.

A 7-year contract with a catcher is probably much riskier than the hazard ratio implies, because there's a good chance that years 5-7 are spent playing every 5th day, or platooning in between DL trips.

While other premium defensive positions can also regress, multiple positions can feed into "4th OF", "utility infielder", etc., whereas "backup catcher" has a tighter labor supply that allows for things like Henry Blanco's 16-year MLB career.

Mar 14, 2014 07:42 AM
rating: 1

This was my immediate reaction when I read this excellent article. I suspect imposing a minimum playing time or WAR threshold on the data would bear this out.

Mar 15, 2014 13:58 PM
rating: 0

I hope Cano lasts longer than Hornsby! He was basically done as a regular at 33 (though he had one last great season at 35) and probably wouldn't have played at all past 37 if he wasn't the manager.

Mar 14, 2014 07:43 AM
rating: 2
BP staff member Robert Arthur
BP staff

Good point. Hornsby fooled me with all the post-30 WAR, and I failed to notice that it was all concentrated in a few years. Eddie Collins is a much better example, since he played productively until age 40.

Mar 14, 2014 08:05 AM

As is Joe Morgan.

Mar 15, 2014 13:57 PM
rating: 1

I loved this article not for it's content alone, but because It has stimulated many more questions as it relates to longevity and productivity... Excellent job!

Mar 16, 2014 06:53 AM
rating: 1
You must be a Premium subscriber to post a comment.
Not a subscriber? Sign up today!
<< Previous Article
Premium Article Pebble Hunting: Soundi... (03/14)
Next Article >>
Fantasy Article Five to Watch: America... (03/17)

Fantasy Article Player Profile: David Robertson
Fantasy Article The -Only League Landscape: National League ...
Fantasy Article Tale of the Tape, Dynasty Edition: Nick Burd...
Fantasy Article Dynasty League Positional Rankings: Top 50 R...
Premium Article Rumor Roundup: Huston Street Might Have Reli...
Pitching Backward: In Search of the Winninge...
Rubbing Mud: A Solution Does Not Exist

Premium Article Pebble Hunting: Sounding the Depths of Each ...
Premium Article Raising Aces: Bush League: Jonathan Gray
Premium Article Going Yard: The Many Swings of Chris Davis
Premium Article Minor League Update: Spring Training Games o...
Fantasy Article Fantasy Auction Values: Third Edition
Fantasy Article TTO Scoresheet Podcast: Episode 9: SS/SIM

2014-04-08 - Premium Article Moonshot: Miguel Cabrera and the Bearable He...
2014-04-01 - Premium Article Moonshot: Cracking the Location Code
2014-03-25 - Premium Article Moonshot: Attrition Over Time
2014-03-14 - Premium Article Attrition By Position
2014-03-12 - The Art and Science of Sequencing
2014-02-06 - Baseball ProGUESTus: Entropy and the Eephus

2014-07-01 - Premium Article Moonshot: Survival of the Fittest: Pitchers
2014-04-08 - Premium Article Moonshot: Miguel Cabrera and the Bearable He...
2014-03-25 - Premium Article Moonshot: Attrition Over Time