To plausibly argue that Kershaw just had the best summer ever, we have to dig deeper into how his year compares to Martinez. We'll consider three factors, two of which tip the scale toward Pedro and one that benefits Kershaw.
Designated Hitters. In the National League, Kershaw pitches to pitchers (who, generally speaking, can't hit). In the American League, Pedro pitched to designated hitters (who are paid to do nothing but hit on that particular day). So you could argue that the best way to compare pitchers is to see how they pitch to non-pitchers. Baseball Reference only has season-long data for this statistic, and you recall that Kershaw's season was marred by a bad start, but the advantage here leans strongly with Pedro.
- Martinez 2000 to non-pitchers: .167 BA; .213 OBP; .259 SLG
- Kershaw 2014 to non-pitchers: .204 BA; .240 OBP; .301 SLG
An Era of Hitting vs Pitching. Kershaw's brilliance comes at a time when pitchers are mowing down hitters at a remarkable clip. Pedro's best season, however, happened when hitters were embarrassing everybody else who walked up to the mound. When you compare the annual offensive output at Pedro's home, Fenway Park in 2000 with Kershaw's home, Dodgers Stadium in 2014, you get a rough sense of the different environments.
- Fenway Park in 2000: 774 runs scored, .272 BA, 2334 total bases,
- Dodgers Stadium in 2014: 598 runs scored, .241 BA, 2009 total bases
The ERA at Fenway in 2000 was 30 percent higher than at Dodgers Stadium in 2014, and yet somehow Pedro had a lower overall ERA than Kershaw by the end of the year.
Quality Starts and Wins. Baseball, the topic of analysis, is all about numbers, but baseball, the sport, is all about winning. And Kershaw, whose team went 20-1 in his 21 starts since June, has been an unprecedented factory of wins, thanks to his consistency. For all of Pedro's genius, he had a higher summer ERA than Kershaw, and his team lost half the games in which he allowed more than two runs. Kershaw, by contrast, allowed more runners, but never allowed more than 3 earned runs in a game.
Martinez 2000, post-June:
- Team record: 13-6
- Games allowing more than 2 runs: 6
- Losses in those games: 3
Kershaw 2014, post-June:
- Team record: 20-1
- Games allowing more than 2 runs: 4
- Losses in those games: 1
Clayton Kershaw's summer of 2014 was more than historic. It was unprecedented. The subject consuming hours on ESPN, whether or not he deserves the MVP, is a small debate that obscures the larger observation that we could be looking at most dominant pitcher in baseball history.
Baseball Reference keeps a list of the starting pitchers with the best career ERA+. At 26, Kershaw is second on that list. He is separated, by a statistical whisker, from the all-time record holder—some guy named Pedro.
*Pedantry preemption: Derek, isn't "most dominant summer ever" an arbitrary measure of pitching quality designed to make Clayton Kershaw look as good as possible while ignoring the fact that many pitchers have had better season-long ERA+ numbers? Yes, that is exactly what this is. But I feel strongly that sports fandom should be present-biased. It's miserable to think that all the best players are already retired and dead and that all the greatest sport accomplishments are behind us. So I've picked a stat that makes his year seem historically exceptional. This is somewhat devious, I guess, I don't feel that bad about it, because ~20 consecutive starts is a reasonable sample size to compare pitchers over time.