Tuesday, January 5, 2010

Beat the drum and hold the phone

The Providence Journal's Joe McDonald reported Tuesday what many have expected: Mike Cameron will displace Jacoby Ellsbury in center field for the Red Sox, shifting the speedy leadoff hitter to left field on a regular basis.

“He was worried that it was a demotion, which it is not,” Red Sox manager Terry Francona told McDonald. “I kind of (assured) him of that. I just think we’re tying to put guys where we think they can make the biggest impression. Cam was great, for a guy who is 37 years old and played center field his whole life. He said, ‘Hey, I’ll play anywhere,' so it was just a decision based on what’s best for our team.”

Cameron might not make the biggest impression in center field, though. Ellsbury might -- and here are three reasons why:

1. Defensive metrics can be unreliable in small samples
As has been thoroughly documented, Ellsbury had a miserable season both in Ultimate Zone Rating (minus-18.6) and in Fielding Bible plus-minus (minus-14).

A year ago, however, both of the same advanced metrics had Ellsbury as an above-average center fielder (plus-3.0 and plus-8, respectively).

Analysts have made clear over and over again that it takes more than one season to assess adequately defensive performance via the new metrics. All we know about Ellsbury so far is that we just don't know.

2. Ellsbury still has a learning curve
Unlike Cameron, who will turn 37 years old this week, Ellsbury has room to improve his breaks on the ball and his routes in the outfield. The 26-year-old has all the speed and athleticism to be an elite center fielder. He just hasn't put it together yet. You could easily make an argument that another season in center field would be just like another year of at-bats -- in other words, just what he needs to keep making improvements.

3. Cameron and the triangle might be trouble
The defensive metrics don't love Cameron unconditionally. Check out the two most recent ballparks in which Cameron has played center field -- images from HitTrackerOnline.com:

Petco Park in San Diego
2006: minus-0.6
2007: minus-10.4

Right-center field: 411 feet
Center field: 396 feet
Left-center field: 402 feet

Miller Park in Milwaukee
2008: plus-15.6
2009: plus-10.3

Right-center field: 374 feet
Center field: 400 feet
Left-center field: 371 feet

Fenway Park in Boston

Right-center field: 383 feet
Center field: 420 feet
Left-center field: 379 feet

At no point does the fence at Miller Park get any farther than 400 feet from home plate. Petco Park's power alleys, on the other hand, have more in common with the triangle in center field at Fenway Park than aspect of Miller Park.

(It's not easy to see relative distance on the diagrams unless you look at where the concentric circles -- 300 feet out and 350 feet out -- are superimposed against the outfield fences.)

If the Fielding Bible's plus-minus numbers are to be believed -- and here we have to pull out the grain-of-salt warning again -- Ellsbury was far better on deep fly balls than on shallow fly balls. He made some of his most memorable catches either up against the fence or back in the triangle in deep center field.

Either way, by replacing Jason Bay with Cameron, the Red Sox have made a dramatic upgrade to their defense in the outfield. Ellsbury, though, might still be a better fit for the triangle in center field than Cameron is.

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