(minimum 1,500 innings pitched)
PLAYER SPAN PLAYER LEAGUE DIFF
Pedro Martinez 1992-2009 2.93 4.40 -1.47
Carl Hubbell 1928-1943 2.98 4.13 -1.15
Lefty Grove 1925-1941 3.06 4.21 -1.15
Hoyt Wilhelm 1952-1972 2.52 3.67 -1.14
Greg Maddux 1986-2008 3.16 4.28 -1.13
Roger Clemens 1984-2007 3.12 4.25 -1.12
Felix Hernandez 2005-2014 3.07 4.15 -1.07
Whitey Ford 1950-1967 2.75 3.80 -1.06
Johan Santana 2000-2012 3.20 4.25 -1.05
Sandy Koufax 1955-1966 2.76 3.77 -1.01
Randy Johnson 1988-2009 3.29 4.30 -1.01
Kevin Brown 1986-2005 3.28 4.26 -0.98
John Smoltz 1988-2009 3.33 4.30 -0.97
Note: ERA became an official statistic in 1913
Source: STATS LLC