Add new comment

Muddyfrog writes,

Is there any correlation on age arc and large men? The reason I ask is

because we're seeing guys like Bryan LaHair, & Mike Morse peak in their late

twenties. Do you think this may be the case for guys like Smoak, Montero, and

Carp? Or more specifically can you single out a particular group or stereo

type a group of players that tend to peak in their late twenties and early

thirties. What's the median peak age?

Provocative question!

Lots of studies have been done on peak age for the whole population.  Here's a series at Hardball Times and here's material from Tom Tango's epic website.  A good player has his 95-100% results from about age 23 to about age 29-30.

 ..............................................................

But we've known that, in its broad outlines, at least since 1980.  To me yours is a much more interesting question:  what is the prototype of the player whose curve is right-shifted on this graph?

.

Q.  What kind of studies have been done?

A.  The ones I've seen don't help us.  Bill James' "Strong Season Leading Index" is discussed here, among other places.  

In that article, the Hardball Times was looking at bustout seasons by Russell Branyan, Aaron Hill and Mark Reynolds, and trying to decide whether those players were "for real."  But there are a couple of problemos there that ace us out...

First, James' SSLI is a rotisserie-type device.  As with the very similar BaseballHQ "Breakout Index," this formula is merely looking at the obvious to decide what the NEXT season will be.  It takes into account age - if you're over 30, you're not likely to have your best season coming up.  It takes into account unlucky BABIP.  It takes into account the Plexiglass Principle, that players are likely to rebound to their career averages.  Stuff like that.  

And it's looking for a SINGLE season with up stats.  It's not really designed to identify the next Raul Ibanez.  I haven't seen any studies that do that, although somebody here may know of some.

.

Q.  Do pitchers count?

A.  Pitchers don't follow age-arc trends.  They learn a new pitch, or they fix their mechanics, and then they become something different.  It's batters that live off "number of pitches in the memory banks."  For hitters, it's a race to see 1,000,000 pitches before their reflexes go at age 32.

But if you're talking about "late blooming" pitchers, probably the most extreme who ever lived was our own Jamie Moyer.  As he began his age-30 season, he had 34 wins, 54 losses and was out of the majors.  As you might have noticed, he had 235 wins in the tank from there.

There are tons of guys like this.  Dave Stewart of the A's.  Randy Johnson, people almost forget, was a joke until he was 29.  People forget that Cliff Lee was a meatball for several years, with little apparent chance of ever getting better.  Jeff Fassero.  Odd that the Mariners' spectacular 1997 rotation featured three of the most radical such ever.

But whoever those guys are, you can't predict them.  Cliff Lee figured out a cut fastball and how to use it; what pitcher couldn't do that, at least in theory?

.

Q.  Since studies don't exist, or you don't know about them, where do you start?

A.  ...