The Umpiring Bias

Bias not in the sense of favoritism, but in the sense of favoring either the offense or the pitchers in a given game.  It is well known among major leaguers that there exist "pitcher's umps."  These are men in black that call a loose strike zone, and give the pitcher a lot more leeway in terms of what is and isn't a strike.  And there are those with a tight strike zone, who force the pitchers to bring the ball more into the middle of the plate.  Not surprisingly the former are associated with lower scoring games with less offense; the latter tend to umpire higher scoring games.  Sam Walker writes in the Wall Street Journal about the choice of umpires made by the American League in the divisional series between the pitching-rich Chicago White Sox and the big bats of the Boston Red Sox.  The White Sox, a team with strong starting pitching and a strong bullpen, got the benefit of "pitcher's umps" for the series.

Last week in the American League Division Series, Chicago dispatched the Red Sox in three straight games. The matchup had been anticipated by fans, in part because it pitted two teams with markedly different strengths: The big-hitting Red Sox, the best offense in baseball this year, against the White Sox and their staff of ace pitchers who shared the American League's lowest earned-run average.

Into this volatile mix, Major League Baseball threw a remarkable group of officials -- a crew of six umpires that stood out among their peers by demonstrating, over the course of the regular season, that the way they called games behind the plate favored pitchers and held down scoring. Just as this formula would dictate, Boston had a terrible time scoring runs, and Chicago swept the series in three games.

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In the Chicago-Boston series, the officials who called the three games -- John Hirschbeck, Bill Miller and Mark Wegner -- were by no means typical. Among the 70 umpires who worked more than 20 games at the plate this year, this trio was well below average in nearly every measure favorable to hitters. In games they called, based on data collected by Stats LLC, these umpires saw fewer runs and fewer players reach base than the average for officials, and they all ranked among the bottom eight in slugging percentage. On the other hand, they were exceptionally friendly to pitchers: Each one posted an average ERA among the 12 lowest in baseball.

The most extreme member of the group was Mr. Hirschbeck, the crew chief, who appears to be the most pitcher-friendly ump in the majors this year. When he was behind the plate, pitchers from both teams allowed an average of 6.6 earned runs combined, two runs lower than a typical ump. More bad news for Boston fans: He ranked 70th out of 70 in hits, on-base percentage and slugging percentage, in some cases by a fair margin.

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Coming into the Sox-Sox series, anyone who studied the umpire numbers might have suspected the Red Sox would struggle. Boston is a team that generates a large volume of runs by encouraging hitters to be patient, take walks and force pitchers to throw strikes. The idea is to pack the bases for the team's two supremely talented hitters, Manny Ramirez and David Ortiz.

Liberal Zone

But in Game One, with Mr. Hirschbeck behind the plate, the Red Sox all but abandoned this philosophy. The team didn't take a single walk and saw only 113 pitches, which is about 20% fewer than the league average. The clear implication is that the Red Sox, knowing the strike zone would be liberal, decided to go with the flow and swing at pitches they might otherwise have passed on. In the process, they scored only two runs.

In the same game, however, the White Sox lit up Red Sox pitching for 14 runs; that was more an indication of Matt Clement's lack of command.  Not knowing where his pitches were headed, Clement couldn't take advantage of the generosity of this plate umpire.  When he missed, he missed by a lot, or missed in the middle of the plate.  As Ralph Cramden would say, bang - zoom!

While no one in their right mind would blame the umpiring selections for the demise of the Sox of Red, it was another hurdle for them to overcome.

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