MLB Single Season Leaders - Earned Run Average

1. Pedro Martinez 1.74 (2000)
2. Roger Clemens 1.87 (2005)
3. Zack Greinke 2.16 (2009)
4. Pedro Martinez 2.22 (2003)
5. Chris Carpenter 2.24 (2009)
6. Pedro Martinez 2.26 (2002)
7. Jake Peavy 2.27 (2004)
8. Randy Johnson 2.32 (2002)
9. Jason Schmidt 2.34 (2003)
10. Andy Pettitte 2.39 (2005)
--- Kevin Brown 2.39 (2003)
12. Mark Prior 2.43 (2003)
13. Tim Lincecum 2.48 (2009)
--- Felix Hernandez 2.48 (2009)
15. Randy Johnson 2.49 (2001)
16. Jake Peavy 2.54 (2007)
--- Johan Santana 2.54 (2008)
--- Cliff Lee 2.54 (2008)
18. Kevin Brown 2.58 (2000)
--- Derek Lowe 2.58 (2002)
20. Jair Jurrjens 2.60 (2009)