In 2012, the Brewers put out less than 69% of the batters who put the ball in play against them, a statistic known as “Defensive Efficiency.” Baseball Prospectus, the venerable baseball statistics website, cheerfully describes that put-out rate as “horrendous.” It rated 29th out of 30 teams in baseball.
In 2013, the Brewers put out over 71% of the batters who put the ball in play against them. Baseball Prospectus would rate this performance as “above average.” The 2013 Brewers rated 6th out of baseball’s 30 teams in this category.
What, exactly, could cause a team to jump from 29th to 6th overall in defensive efficiency, in just one season?
One factor to consider is simple luck. A defense’s put-out rate is simply the reverse of the opposing team’s Batting Average on Balls in Play (BABIP) against them. Long-time readers of this blog know that BABIP is notoriously volatile. Although the league-wide BABIP this season averaged .297, team pitching staffs were all over the place: the lowest BABIP belonged to the Reds (.273), while one of the highest BABIPs was allowed by the Tigers (.306). The fact that batters had the hardest time putting the ball in play against the Reds, who play half their games at Great American Ballpark (a home run hitter’s paradise), while having one of the easiest times against an elite pitching staff (Detroit), tells you plenty about the variance of BABIP.
Of course, defense plays a part in those ratings. Over the last few years, the Reds have been an excellent defensive team, while Detroit has been content to put statues like Prince Fielder and Miguel Cabrera on the diamond in exchange for their batting prowess. And good defenders should help improve their team’s defensive efficiency. Good defenders, most obviously, will commit fewer errors. They throw out more runners, prevent singles from becoming doubles, and can simply take away home runs, as Carlos Gomez demonstrated on his way to a Gold Glove this year. So, let’s consider the idea that the Brewers’ defensive improvement may have resulted in part from playing better defense. How do we find that out?
The traditional rating of defense revolves around the assignment of “errors” by the stadium’s official scorer. Players would then be judged by their “fielding percentage” —the percentage of plays on which they did not have an error. Although errors are still tracked, errors (and fielding percentage) are no longer taken seriously as a fair measure of evaluating player defense. Among other things, error assignment tends to vary among official scorers; it also tends to let players off the hook who are too slow or otherwise inept to get to the ball in the first place, while sometimes punishing those who reach the ball and try to make a difficult play. For what it is worth, the Brewers’ fielding percentage — the number of plays in which they did not commit an error — ranked identically in both 2012 and 2013: 23rd out of 30 teams in baseball. So even you take “the error” seriously, which you shouldn’t, you won’t find any explanation there.
Fortunately, we’ve made progress in developing some better defensive statistics. These statistics try to compare the performance of a player in defending each play to what an average player would be expected to do in that particular situation. Each play is then tracked, and the results totaled, over the course of a season to quantify how many runs the player has prevented or allowed, as compared to an average player. Although their exact methods are more complex, both Defensive Runs Saved (DRS), as well as the season-adjusted Ultimate Zone Rating (UZR/150) statistics track individual player performances in this way. When added up across an entire roster, these statistics help show whether the team, in the aggregate, was above or below average overall in making plays and minimizing runs. Because both methods require judgment calls made by a subjective evaluator, it is best to consider both methods together rather than just relying on one or the other.
So, do these advanced defensive statistics shed any light? In fact, they do. Because run environments and schedules can vary, I’ve stuck with overall team rankings, rather than the individual numbers for each statistic. Here’s what we find:
- UZR/150: 19th of 30
- DRS: 11th of 30
- UZR/150: 13th out of 30
- DRS: 4th out of 30.
The two measures for the Brewers in 2012 average out to a ranking of 15 out of 30: basically right in the middle in terms of their ability to make plays. The overall put-out ranking of 29th, therefore, suggests that the Brewers simply suffered bad luck in the field in 2012.
The 2013 season was a different story. The Brewers ranked 6th in put-outs. Was this ranking fairly earned? This time, it actually was. Averaging the UZR and DRS assessments provides gives a ranking of about 9th in baseball, a solid above-average performance.
So, in the end, there is some good news: the Brewers actually were an above-average defensive team overall last year, and had the results to show for it. The bad news, unfortunately, is that 2012 demonstrates they may not be so lucky next year, even if they remain a decent-fielding team.
- Baseball Prospectus: Team Pitching Statistics
- Baseball Prospectus: Glossary