How Jacob deGrom’s 2018 season for the New York Mets compares with the best pitching seasons in baseball history
Jacob deGrom’s 2018 season for the New York Mets has been widely hailed, and within the next 10 days is likely to culminate in his winning the Cy Young Award. But how does it fit contextually with other great pitching seasons?
Answering that question requires an objective system of cross-era measurement. Beyond being objective, it should be simple, and it should factor in the various stylistic changes in pitching styles over more than a century, meaning it should be fair in a cross-generational sense.
The following system meets all those criteria. The ratings are based on the standard deviation of each pitcher’s earned run average compared with all other pitchers who worked one inning per scheduled game that season.
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Using standard deviation normalizes all cross-era stylistic distinctions because it compares the excellence of pitchers with all those actually doing the same thing under the same stylistic and playing conditions. In other words, it becomes possible to fairly compare modern pitchers with those of earlier generations.
Here are the salient findings:
1. deGrom’s 1.70 ERA rates as 2.39 standard deviations below the average standard deviation for the 28 National League pitchers who pitched at least 162 innings during the 2018 season.
2. That -2.39 “score” is the best produced by any National League pitcher since 1996, when the Florida Marlins’ Kevin Brown produced a 1.89 ERA that was 2.50 standard deviations better than the NL average for that season’s qualifying pitchers.
3. It is the best by any pitcher in either league since Zach Greinke’s 2.16 ERA for the 2009 Kansas City Royals,, which was 2.73 standard deviations better than the AL average.
4. It is the fifth best in the National League in the divisional era (since 1969). Here are the four ahead of deGrom, showing the pitcher’s ERA and his standard deviation score.
- Greg Maddux, 1995 Atlanta Braves, 1.63, -2.71
- Dwight Gooden, 1985 New York Mets, 1.53, -2.55
- Greg Maddux, 1994 Atlanta Braves, 1.56, -2.55
- Kevin Brown, 1996 Florida Marlins, 1.89, -2.50
5. It equals the 12th best score in the 142-year history of the National League. Here are the NL seasons ahead of or equal to deGrom’s, showing the pitcher, season and team, ERA and score.
- Three-Fingered Brown, 1906 Chicago Cubs, 1.04, -2.81
- Amos Rusie, 1894 New York Giants, 2.78, -2.78
- Bob Gibson, 1968 St. Louis Cardinals, 1.12, -2.76
- Grover Cleveland Alexander, 1915 Philadelphia Phillies, 1.22, -2.74
- Greg Maddux, 1995 Atlanta Braves, 1.63, -2.71
- Warren Spahn, 1953 Milwaukee Braves, 2.10, -2.68
- Dwight Gooden, 1985 New York Mets, 1.53, -2.55
- Greg Maddux, 1994 Atlanta Braves, 1.56, -2.55
- Dolf Luque, 1923 Cincinnati Reds, 1.93, -2.54
- Carl Hubbell, 1933 New York Giants, 1.66, -2.54
- Kevin Brown, 1996 Florida Marlins, 1.89, -2.50
- Fred Anderson, 1917 New York Giants, 1.44, -2.39
- Jacob deGrom, 2018 New York Mets, 1.70, -2.39
6. It is the 31st best pitching season in all of baseball history. The 10 best are:
- Pedro Martinez, 2000 Boston Red Sox, 1.74, -3.79
- Pedro Martinez, 1999 Boston Red Sox, 2.07, -3.18
- Dutch Leonard, 1914 Boston Red Sox, 0.96, -3.02
- Walter Johnson, 1912 Washington Senators, 1.39, -2.82
- Mordecai Brown, 1906 Chicago Cubs, 1.04,-2.81
- Lefty Grove, 1931 Philadelphia Athletics, 2.22, -2.77
- Bob Gibson, 1968 St. Louis Cardinals, 1.12, -2.76
- Grover Cleveland Alexander, 1915 Philadelphia Phillies, 1.22, -2.74
- Ron Guidry, 1978 New York Yankees, 1.74, -2.74
- Zach Greinke, 2009 Kansas City Royals, 2.16, -2.73