How much will the Sox improve run prevention?

Boston’s emphasis on defense this off-season has been well known. New acquisitions Marco Scutaro, Adrian Beltre and Mike Cameron all have strong reputations for their defensive abilities. Boston also went out and signed the top free agent pitcher in John Lackey.

The question many fans are wondering is just how much they will improve from last year. I decided to look at last season’s UZR numbers (courtesy of fangraphs) from their former player and new signings at each position.

At the third base position Mike Lowell and Kevin Youkilis split time and combined for -12 runs in 2009. Adrian Beltre missed significant time with injuries but still racked up 14.3 UZR, which is good for a 26 run swing.

The Sox upgraded at shortstop by singing Marco Scutaro. Scutaro posted a 0.9 UZR in ’09 and Boston’s trio of Alex Gonzalez, Nick Green, and Julio Lugo posted exactly the same number so no net change.

Boston brought in Mike Cameron to patrol center field. Cameron’s 2009 UZR of 10 was 28 runs better than Jacoby Ellsbury. Ellsbury had a dismal year in the field according to UZR, which had him at -18.6 runs.

Ellsbury will be making to shift to left field where he will take over for Jason Bay. Ellsbury has a small sample size of innings in left although CHONE projects him to be around +6, which is where I would cautiously predict as well. This is a 19 run upgrade over Bay’s -13 UZR last year.

All told that is nearly a 74 run difference in defense alone before taking into account the addition of John Lackey to the staff. Lackey himself could keep an additional 30-40 runs off the board.

Last year the Red Sox allowed 736 runs on the year. Allowing for some regression to the mean I can see the Red Sox improving their run prevention by 80-100 runs. This would put them around the ballpark of 630-650 runs allowed next season.

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  1. Adam B. said...

    Predicting a 24 run upswing from last year for Ellsbury is a bit much considering the following:

    1) Tango’s studies on the difference in runs between someone who plays both shows less of a net gain
    2) LF gets less balls in play than CF
    and this is the big one
    3) Boston LFs tend to have lower UZRs because of the wall

  2. PunchesInBunches said...

    I have a very hard time believing the red sox are will shave off 100 runs or about 14 percent of runs allowed from last year just by moving their cf from last year to left and bringing in cameron to patrol center in addition to signing a pitcher who has made just 50 starts the past two seasons combined. Seems like a lofty number for such marginal changes.

  3. Alex Pedicini said...

    @ Mike Rogers

    Yes it probably is not the most accurate method to use last year’s numbers which is why I adjusted the final numbers down to account for regression.

    This is simply a projection of what MAY happen this year. Even if Boston decreases their runs allowed by 40-50 runs this is a sizable amount.

  4. Mike Rogers said...

    Yeah, that’s what I figured Alex. I am continually envious of Boston and Tampa’s front offices. I really, really wanted Mike Cameron for LF.

  5. D Leaberry said...

    Mike Cameron has hit .250 or below for three years running and he’s 36. Jacoby Ellsbury becomes one of the least powerful sluggers starting in leftfield in the American League.  If Cameron shows age decline(eg. David Ortiz) and hits .230 with a drop in power to 15 home runs or so, we’ll see how well this plays for the Red Sox.

    Getting Beltre for third and forever keeping Youklis at first seems wise, however.

  6. Alex Pedicini said...

    Valid point, Adam. However, many fans and scouts agree that Ellsbury is a solid defender and 2009 was rather flukey. He did post a 16.5 UZR in 2008 including 9.3 in 346 innings in left field. He also posted well above average TZ numbers in the minor leagues as well.

    Ellsbury’s speed and range should allow him to cover much more ground than a typical left fielder. Fenway will not help him but he could still save plenty of runs on the road.

    Here is an interesting debate regarding his skills vs. stats;=#entry2725283

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