Revisiting Preseason Outfield Defense Expectations

Before the season Dave Cameron looked at the trend of some teams putting a greater emphasis on outfield defense. He specifically noted that the Mariners, Rays and Orioles were planning on effectively playing three center fielders. The outfield defense plan has worked out well for the Mariners and Rays, but not for the Orioles.

Ichiro Suzuki, Franklin Gutierrez and Endy Chavez were just as good as advertised and the Mariners limited defensive butchers Wladimir Balentien‘s and Ken Griffey‘s time in the field. Chavez is out for the season with an injury but his playing time has largely been replaced Ryan Langerhans, also a very good defender. By UZR’s measure the Mariner’s outfield defense has saved 30 runs over average, playing a big part in keeping them in AL West contention.

The Rays outfield has been worth 25 runs over average, second only to the Mariners. Their outfield innings have gone to equally to Carl Crawford, B.J. Upton and the Gabe platoon, with a little sprinkling of innings from Ben Zobrist. All of these guys have played well this year, right in line with their career UZRs.

For the Orioles things have not gone as well, giving up an additional 20 runs in outfield defense. Nick Markakis and Adam Jones are two of the game’s up-and-coming star outfielders and their futures are bright, but their defense this year has not been good. Together they have given up over 15 runs, but it is important to remember this does not mean we should expect them to be poor fielders going forward. UZR and other defenses metrics, by all accounts, take huge numbers of innings before they become predictive and are subject to big fluctuations even of the course of an entire season.

Markakis and Jones came into this season with great fielding numbers in 2008. Markakis at +11 UZR/150 in over 1300 innings in RF and Jones at +11 UZR/150 over 1000 innings in CF. This year Markakis is -16 UZR/150 over 760 innings in RF and Jones -12 over 600 innings. This new data put together with the old tempers our expectations; maybe Markakis is only a +5 to +0 corner outfield and maybe Jones is just a +5 to +0 center fielder. With so few innings it is also important to weigh our projections going forward with scouting reports, at least one set of which calls the two great defensive outfielders.

Luke Scott and Nolan Reimold picked up most of Felix Pie‘s, the third member of the Orioles planned three CF outfield who couldn’t hit enough to justify his playing time, innings and have played poor defense. Scott has a history as a +5ish corner outfielder and Reimold was projected as an average corner outfielder, so their performance should get better. Going forward we shouldn’t expect the Os outfield to play as bad as it has, but we can’t expect them to play like three center fielders either.




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Dave Allen's other baseball work can be found at Baseball Analysts.

13 Responses to “Revisiting Preseason Outfield Defense Expectations”

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  1. Xeifrank says:

    Any idea on the variation of UZR and at how many innings we should regress 50%, and to what should we regress to, a 0 UZR?
    vr, Xei

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  2. mjmetro says:

    can anyone link to work on how many innings it takes UZR to stabilize? i’d be really interested in that.

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    • Ray says:

      because UZR changes each year, for each position, it is hard to find trends for stability.

      I sort of remember an example of Jimmy Rollins on how his UZR has changed due to other shortstop’s UZR going up or down, but his defense never really changed

      I may be wrong

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  3. MGL says:

    How many coin flips does it take for the heads/tails percentage to stabilize? 631? 285? 1,318?

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    • Dave Allen says:

      After 100 coin flips I am over 95% confident I will be between 40 and 60 heads. Could one make a similar statement about UZR, after N innings I am 95% (or 50%) confident a player’s UZR/150 is within X runs of that player’s true talent.

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  4. MGL says:

    It depends a little on the position and no one know for sure, but a good rule of thumb is that after a season’s worth of UZR, you can regress his UZR 50%, maybe a little less. Now that is based on back to back years of empirical UZR and does not necessarily mean that regressing one season 50% tells is a player’s true talent defensive value, but it is probably close. The reason that is the case is that if UZR is actually not an accurate stat it still could be reliable enough for only a 50% regression after 1 year. For example, if we give a child an IQ test once, it is likely that each child with a high or low score will regress – and let’s just say that it is 50% – if we give him another test – the same test. But if the test is a crappy one – i.e., it does not measure intelligence well, regressing that first IQ test 50% is not going to give us a good estimate of that child’s intelligence. It will only give us a good estimate of how he will score if he takes the test again.

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  5. MGL says:

    I didn’t mean to be snark in my first comment above – actually I did. The reason is that words like “stabilize” are meaningless in this context. Obviously (I think everyone who has ever heard of this website knows this) the more data you have, the more it represents a player’s true talent, assuming that the data is a reasonably accurate reflection of that talent. There is no magic number at which point it “stabilizes.”

    And I have no idea what this means (the words “career trends”):

    “One main problem test defensive metrics is that they are new and no good career trends can be made yet.”

    But the poster states it as a fact, so I have no doubt that it is true, especially since that poster is actually a major league player…

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  6. Grant says:

    I have only see Reimold play a few times, but from what I saw he is a well below average defender. Just seeing the route’s he takes, his body type and instincts when actually making the catch, makes it hard for me to believe that he will ever be league average. I’d say -15 to -5 at a corner spot.

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  7. UZR IS A JOKE says:

    Maybe Adam Jones’ UZR is so bad because UZR is a freakin’ joke. He has gotten to more balls than any other CF in the league. He has more putouts than expected outs, and I’m to believe the only other CF he is better than in RngR is Vernon Wells? Give me a break.

    But keep pumping out this crap. Maybe enough GMs will start buying this garbage, and the GMs who realize the best way to judge a defenders ability is by watching him play the game, at least for now.

    Maybe if the data on how the number was came by was released, it could be viewed by as many eyes as are needed to find it’s flaws. I really do hope that eventually there are some meaningful defensive metrics out there, but as for right now, UZR is not meaningful.

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    • Jason T says:

      Yes, because UZR doesn’t care for Adam Jones this season makes it worthless. Sometimes good systems makes mistakes. One could say the same thing about democracy on occasion.

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