Felix Hernandez
Hernandez is the paradigmatic illustration of an "on-the-fence" candidate.
Between 2009 and 2015, he may have been the American League’s best pitcher. For those seven seasons he had a 104-65 record, he won two ERA titles, he twice led the league in starts, and he pitched a perfect game.
Those numbers compare favorably with previous honorees who made the Hall thanks to an elite "peak".
To cite one example, between 2009 and 2014, Hernandez’ ERA was 2.74. Between 1961 and 1966, Sandy Koufax’s ERA was 2.19. But Koufax rang up his ERA in an age when the league average was just 3.54, making him 39 percent superior to the league as a whole. Hernandez’s 2.74 average was 43 percent better than the 4.08 American League average ERA during his peak.
But peak candidates almost always face the hurdle imposed by their non-peak performance. Hernandez actually pitched for 15 seasons, and outside those seven peak years, his record was 65-71. It’s no small period of comparative mediocrity, comprising more than 1,100 innings, and it’s the reason why his career ERA is 3.42, not something close to the 2.74 of his prime years.