From: genetic+@pitt.edu (Dr. Dave)
Newsgroups: rec.sport.baseball
Subject: Defensive Positional Value (was AL ROY, long ago)
Date: 30 Sep 92 14:53:02 GMT
Organization: Department of Industrial Engineering

Thus spake spira@panix.com (Greg Spira):
>Okay, but forget offensive value.  Neither of us is interested in that
>right now.  What we're interested in is whether Jeff Blauser's defense
>is more valuable than Devon White's because of the extra difficulty of
>the shortstop position.  

Quite the opposite, I would think.  Blauser's defense hurts the Braves *more*
because shortstop is a high-leverage defensive position: lots of opportunities,
and a wide range of ability levels among league regulars.

>Now, I think we both agree that Devon White
>is a much, much, much better centerfielder than Blauser is a shortstop.
>Yes, any other shortstop the Braves would put out there would be more
>valuable defensively.  But I don't think that means Blauser has negative
>defensive value, because you can't compare him just to other shortstops.

Why not?  Only other shortstops play short, by definition.  

I've recently become convinced that Valentine has it right: the ability to
play a difficult (or high-leverage) defensive position is an *offensive* plus
to the team.  The only other intrinsic value in being able to play shortstop
at a tolerable level is the presumed ability to also play less demanding
defensive positions if necessary.  There's no bonus value just for being able
to play shortstop other than the increased offense from a weak-hitting spot in
the lineup.

>You have to measure his defense in terms of all fielders.

This is done by comparing to a league-average fielder at that position, and
seeing how many extra hits (and bases) you give up, how many DP's you start,
how many baserunner kills, etc.  Only then can you compare defensive values
across positions.

>Now, I have no way of measuring this, and I presume you don't either.

I don't see why not.  Sort of a "defensive runs created"...

>[Aside - Has anyone noticed that McWeekly's idiotic TAG system rates Frank
>Thomas as one of the five most valuable DEFENSIVE players in baseball]

I stopped reading the TAG ratings as soon as I was convinced that I knew how
they were being computed.  What a moronic system.

>To move to an easier example, would you agree that the worst shortstop
>is worth more than the best first baseman? Or a DH?

Absolutely not.  The worst shortstop is a replacement-level player, and thus
has almost zero value.

>What I'm saying, obviously, is that the ability to play shortstop for a
>major league team has a value in and of itself.  

I disagree.  The value of a player who can play shortstop is precisely what
he gives you that you can't get from a replacement level shortstop.  That has
to include offense; it's a package deal.  A guy who can play shortstop gives
you just what Val said: (His offense - avg. regular) + (His defense - avg. reg)

>Only after you establish
>that value do you add on more value based on exactly how good at that
>position he is.

What is the value, to a major-league roster, of a guy who fields like Ozzie
Smith in his prime, but bats .000 in 1000 plate appearances, with no walks?
Zero.  What is the value of a guy who fields like Howard Johnson at short, 
and bats like Raphael Belliard?  Also zero.  

>>If we're going to normalize offensive numbers by position, why not normalize
>>defensive numbers?
>
>Well, we should normalize defensive numbers by position.  That's precisely
>what I'm arguing for.  A bad effort at shortstop should be normalized to
>make it worth more than a good effort in centerfield.

Even if it isn't?  :-)

As always, I'm claiming that a player's value is what he gives you that other
teams aren't getting from their guy(s) at that position.  In that analysis, 
the intrinsic value of "being a shortstop" cancels out, because everyone has
it.  If competent fielding shortstops were so rare that not every team could
lay hands on one, things would be different.  But every team can; it's just
that some of them aren't major-league hitters.  (And don't tell me about the
Dodgers; they could have signed Alvaro Espinoza any time...)



-- 
       David Tate        |"Out of the dugout endlessly swinging,
 dtate@unix.cis.pitt.edu | Out of the manager's throat, the sound fundamentals,
 Prof. of Story Problems | Out of the six-month season..."            
 Member ORSA, TIMS, SABR | 	Walt "Lefty" Whitman
Newsgroups: rec.sport.baseball