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 Greene, 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.

Red Sox Front Office Strategy

The 2009-2010 off-season has been a busy for Red Sox Nation. It has also demonstrated a clear strategy by the baseball operations staff as they make a strong commitment towards run prevention. Instead of targeting a high profile bat (Adrian Gonzalez comes to mind) they have signed two of the best defenders at their respective positions in Adrian Beltre and Mike Cameron. Oh yeah, both can hit a little bit as well. Again with the signing of John Lackey they have also shown their willingness to pay top dollar for run prevention, pitching and defense.

There have been several studies done on post-season performance and most of the results seem to indicate that its pitching and defense, not run production, that is most important in winning the World Series. Obviously luck has something to do with it as well, but this off-season the Red Sox have done their best to assemble a team that has the right ingredients to make a deep post-season run. This may look like a different Red Sox team that in years past, but, on paper at least, this may be the best team we have had in years.

Even better is that the Sox will have a significant portion of their payroll coming off the books following the 2010 season which will certainly pave the way for the organization's top prospects, many of whom may be ready to make an impact by 2011.