Though a "quality start" is hardly the best measure of a starting pitcher, it can tell us a lot about consistency. If a pitcher regularly puts up a quality start, his team more than likely has a great chance to win his starts.
A quality start is defined as throwing at least six innings while allowing no more than three runs. So the baseline here is a 4.50 ERA (6 IP, 3 ER), but, again, doing this well or better definitely helps give us a good beat on whether or not a starter gives his team a chance to win.
Here are the top 10 starters in 2013 in quality start percentage, thanks to baseball-reference.com:
1. Clayton Kershaw, Dodgers: 82%
2. James Shields, Royals: 79%
3. Max Scherzer, Tigers: 78%
4. Chris Sale, White Sox: 77%
4. Cliff Lee, Phillies: 77%
4. Matt Harvey, Mets: 77%
4. Bartolo Colon, Athletics: 77%
8. Cole Hamels, Phillies: 76%
8. Adam Wainwright, Cardinals: 76%
10. Travis Wood, Cubs: 75%
Some names that might surprise those who only judge pitchers on win-loss record (yes, those people still, sadly, exist) would be Sale, Hamels and Wood. Those three were harmed badly by poor run support (Wood had second worst in the league, Sale was sixth worst and Hamels was 18th worst), though, in addition to other factors that were team-related and not individual-related.
For example, ESPN.com posts a stat called "tough losses," which is games the starting pitcher puts together a quality start and loses. Hamels and Sale tied for the MLB lead with seven tough losses. Wood was right behind with six.
Anywho, onto the opposite end of the spectrum. Here were the worst pitchers in 2013 in terms of quality start percentage, out of 128 qualifying starters:
1. Barry Zito, Giants: 24%
2. Juan Nicasio, Rockies: 29%
3. Jason Hammel, Orioles: 35%
3. Jeremy Hellickson, Rays: 35%
3. Dylan Axelrod, White Sox, 35%
3. Chris Capuano, Dodgers: 35%
7. Lucas Harrell, Astros: 36%
7. Trevor Cahill, Diamondbacks: 36%
9. Edinson Volquez, Padres/Dodgers: 38%
9. Wade Davis, Royals: 38%
9. Mike Pelfrey, Twins: 38%
9. Phil Hughes, Yankees: 38%
9. Scott Diamond, Twins: 38%
9. Erik Bedard, Astros: 38%
Yikes, Zito. Giving your team a quality start -- again, with a liberal baseline for success -- less than one time every four outings for $20 million. That's rough.