Last season the Brewers finished with a 0.592 winning percentage. This season their winning percentage is down to 0.456. The difference is almost purely attributable to a drastic reduction in fielding efficiency.
I measure the three main baseball categories (batting, pitching, and fielding) by comparing the number of bases gained or allowed in each category to the number of outs produced by that category. Base to Out ratio is highly correlated with the number of runs produced.
For batting, the number of bases gained includes bases gained by walks and hit batsmen, as well as bases stolen. The number of outs produced excludes outs produced by sacrifice bunts. For pitching, the number of bases allowed includes 4 bases for each home run and one base for every walk or hit batsmen. No other bases are charged to the pitcher, because he has minimal control over every other kind of base production. Similarly, the pitcher is only credited with producing outs that come from strikeouts. Every other kind of base allowed by the defense and out produced by the defense is attributed to fielding.
In 2011, the Brewers offense produced 0.718 bases for every out they made. That was outstanding. This season the offense is only producing 0.696 bases per out, but that’s pretty close and still pretty good.
In 2011, the Brewers defense (pitching plus fielding)allowed only 0.637 bases for every out produced. That was very good. In 2012 the Brewers are allowing 0.715 bases for every out, which is very bad, and which explains their diminished winning percentage. The extra bases allowed by the defense translates into extra runs for the opposition.
It’s the Fielding
The increase in bases allowed per outs made can be attributed entirely to the Brewers poor fielding. Believe it or not, by my standards the Brewer pitching is actually improved. In 2011 the pitchers were giving up 0.844 bases for every strikeout, this season they are only giving up 0.828 bases per strikeout. But the fielding has been TERRIBLE. In 2011, the fielding was a very good 0.504 bases allowed to outs produced whereas in 2012 the average has increased to 0.661. That’s awful. In fact, it is the worst in the National League. And it is the reason why the Brewers are losing so many games despite their decent run production.
Who is to blame? A: Rickie Weeks (and others)
The problem with my fielding statistic is I cannot isolate blame. However, if we look at the defensive metrics provided by Fan Graphs, we get some insight.
The biggest defensive liability, per play, is Aoki. He is an incompetent outfielder. In gross terms, however, the problem is 2nd baseman Rickie Weeks. He just doesn’t make enough outs in the field. He hasn’t done so since he came up, and he is not getting better.
Other bad defenders include some surprising names: Corey Hart, Carlos Gomez, and Alex Gonzalez. Each of those players have produced strong defensive numbers in the past.
The great irony is Ryan Braun. At the beginning of his career, his defense was putrid. He is now one of the more solid defensive players in the Brewers starting 9.
Room for optimism
Here’s why I’m optimistic. Most of the “extra bases” have come from much poorer play in the outfield (if Weeks misses a play, its usually a single; when Aoki doesn’t catch the ball it usually means extra bases). If the team can shore up their outfield defense, they could turn this season around. And they have the talent. They just need some health.