“UZR

Suppose you know how often a ball is bit at the 45-foot mark between 2B and 3B, and suppose you know that the average SS turns all balls hit to that spot into an out 80% of the time. Suppose that Jimmy Rollins gets 100 plays like that, and he turns 90 of them into an out. We say that Rollins is +10 plays above average.

UZR looks at each foot mark between 3B and 2B, and looks to see how often all SS made an out at those marks, and goes through the exercise above.

(Actually, not each foot, but each angle. Same thing.)

Not only the vector, but also the distance from home plate is considered. Again, it’s the same exercise, but more variables are considered.

Not only vector and distance, but whether it’s a GB, FB, LD, Pop. And the hardness hit of the batted ball. And whether the pitcher is a GB pitcher or not. And the park. And the runners on base and outs. And if the batter is lefty or righty.

Now, it doesn’t necessarily break each play out into its own bucket, because otherwise, you won’t have enough other plays from other SS to compare against from the same bucket. So, it buckets a certain number of those variables, and applies adjustments for the other variables.

At its most basic, it answers this question: “Given that an average fielder faces this exact distribution of batted balls, how many outs did our fielder actually record against the expectation?””

Solely looking at the last question posed, you would have to think the size of LF in Fenway would have an affect, perhaps more substantial than any other park in baseball, on UZR. The Crawford boxes would also have an affect by this logic. The converse is Coors, which IMO has one of the largest outfields in baseball (not having looked at total dimensions).

]]>Manny

2004 -11

2005 -12

2006 -11

2007 -14

2008 – 3

2009 – 7

Bay

2004 +5

2005 0

2006 2

2007 -8

2008 -8

2009 -1

FWIW, Cameron

2004 -3

2005 0

2006 +3

2007 +5

2008 +7

2009 +3