— Where BTF's Members Investigate the Grand Old Game
Sunday, November 03, 2002
And the Beat Goes On: Derek Jeter and the State of Fielding Analysis in Sabermetrics
In the initial offering in his survey of defensive analysis, Mike charts the terrain to be covered.
Derek Jeter gets his share of praise for his defensive skills. In 2000,
American League managers rated him second among AL shortstops defensively,
behind only Omar Vizquel. In the 2001 AL Divisional Series, he made spectacular
plays in back-to-back games, first making a backhand flip of an off-line throw
to nail Jeremy Giambi at the plate, then tumbling head over heels into the
stands to grab a foul ball.
Derek Jeter also takes his share of criticism for his defensive performance.
Year in and year out, he makes fewer plays than any other AL shortstop. He ranks
at the bottom of the list in most well-known statistical measurement systems for
notes that Jeter doesn’t even match the level of
performance turned in by his backups, while
of Baseball Prospectus wrote this
“Defensively, Derek Jeter is positively horrible. He takes forever to release
the ball, has no range, his footwork was best described by Joel Grey in Remo
Williams: The Adventure Begins and he will join the ranks of the defensively
horrific who win Gold Gloves because of their charisma, the occasional highlight
reel play, exposure and their offensive production.”
Sentiments similar to those above are expressed on internet mailing lists, in
newsgroups, here on Baseball Primer, and on other Web sites. Sabermetric
analysts are nearly unanimous on this subject - Derek Jeter is a horrible
defensive player. Almost every fielding analysis method out there ranks Jeter as
a below-average defensive shortstop, and most rank Jeter at the very bottom of
the list. But after evaluating the play-by-play record, I think those rankings
say more about the problems with existing statistical methods for evaluating
fielding than they say about Jeter’s fielding skill.
This series of articles expands on a presentation that I made at the 2002
SABR convention in Boston. In this initial article, I will lay out the series of
“first principles” that I believe should be an essential part of any defensive
analyst’s tool kit. In future articles, I will evaluate existing fielding
methods using Derek Jeter’s 1998-2000 season performance as an example, and
provide an assessment of each of those methods drawing on data from the
play-by-play data I have licensed from Gary Gillette and Pete Palmer for those
seasons. I will also look at the play-by-play data to assess Jeter’s fielding in
I am not here to evangelize for (or against) a specific approach to fielding
analysis. I want to illuminate the problems inherent in current methods for
evaluating fielding, and to help readers understand that no single approach,
whether it be one of the zone-based systems or Win Shares or Clay Davenport’s
methods or Context-Adjusted Defense or Mike Gimbel’s system or Tom Tippett’s,
can be considered the definitive method for evaluating fielding. Most of the
authors of the aforementioned systems know their limitations, and make it
clear the extent to which those systems are limited. The rest of us need to have
the same awareness.
First Principles of Fielding Analysis
In evaluating a system for analyzing fielding performance, I make use of the
following “first principles.” I realize that some of these are not universally
accepted among analysts; nonetheless, after spending countless hours evaluating
the information available in the play-by-play data, it is my belief that a
fielding analysis system needs to be based on these principles if it hopes to
capture fielder skills accurately - specifically differences in fielder
positioning, which is in my opinion a little-realized aspect of fielder skill
that is not commonly addressed by analysts.
There is no such thing as a “routine out” or (except for balls that leave
the field of play) an “uncatchable ball.” Fielding skill includes
positioning, quickness in reacting to the ball when hit, and hands; the first
two of these combine to form what we commonly call “range.” If a fielder is
positioned correctly, the ball is likely to be hit right to him and it looks
like a routine out. If a fielder reacts to the ball quickly, he can usually
get to a position right in front of the ball when it gets to him and again it
looks like a routine out. But if the fielder doesn’t position himself properly
or is slow to react when the ball is put into play, suddenly the play doesn’t
look quite as much like a routine play any more. Even if he does react
properly, if he mishandles the ball the routine out will likely go away.
Similarly, an uncatchable ball for one fielder is often catchable for another
fielder who is positioned a bit differently, or who reacts to the ball more
When a ball that remains in the field of play is not converted into an
out, the fielders should be held responsible for that failure, whether the
result is called a hit or an error. I don’t see any other way to include
all of the key aspects of fielding skill - positioning, quickness to the ball,
and hands - in an analysis of fielding unless one starts with this
Fielders should not be penalized, or rewarded, for plays that are made by
other fielders. I think most people would agree with this one.
Fielders should be penalized when plays are not made that they could have
made, given likely positioning of the defense. Note that I say “could have
made,” not “should have made,” here, because in many cases we don’t know
enough about the positioning of the fielders to make an accurate determination
of responsibility for a ball in play. If all we know is that a team allowed a
hit on a ground ball through the SS hole, we can’t assume that because the
average 3B fields the ball 50%, the average SS fields it 40% of the time, and
10% of the balls through the SS hole are not fieldable, that we should divvy
up the responsibility that way. We don’t know enough to determine whether the
3B or the SS, or both, or neither, had a chance to turn that specific ball
into an out. We don’t know who was hitting, who was pitching, if the infield
was up or back or at double-play depth, whether the SS had broken to cover
second on a steal attempt, whether the 3B was up defending against a bunt
attempt, or other variables that affect fielder positioning. All we know is
that either the SS or the 3B could have been in position to make a play
on the ball with the most likely alignments of the defense, and we also can be
nearly certain that no other fielder could have been in position to make a
play under likely alignments of the defense. We can reasonably conclude that
both the SS and the 3B should be penalized because the play was not made, but
we can’t determine which one was most responsible, or the extent to
which either or both might have been responsible. The only sure way to ensure
that both fielders receive their share of the responsibility is to treat both
fielders as being fully responsible for missing the play.
Fielders cannot be evaluated without accounting for the effects of team
defensive context. Fielder positioning is driven by the distribution of
balls in play against the team, and a fielder’s ability to cover a particular
area of the field is, in turn, driven primarily by his positioning. Therefore,
a SS who handles 45% of the balls in play in the SS hole behind the pitching
staff of the Yankees can’t reasonably be assumed to handle 45% of the balls in
play in the SS hole behind any other pitching staff, or (more importantly) 45%
of the balls in play in the SS hole behind a league-aggregate pitching staff.
One must evaluate a fielder in the context of his team’s distribution of balls
in play, because it is that distribution - no other - which defines his
opportunities to make plays.
Posted: November 03, 2002 at 05:00 AM | 25 comment(s)
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