Going by the book, or Wikipedia, or Fangraphs, or any other glossary of baseball statistics, a quality start is a start in which the pitcher goes at least six innings and allows a maximum of three earned runs. Lately, I've been contemplating the importance of quality starts. Personally, I think a quality start should be defined as "a start in which the pitcher gives his team a reasonable chance to win." In many cases, that does mean a starter needs to go six innings and hold the opposition to three runs. However, I believe the exact parameters for a quality start should vary depending on the strength of the team's lineup, bullpen and opposition.
Take a look at Dan Straily's start on Saturday. Yes, he lasted six innings and allowed three runs, but considering that he was facing Felix Hernandez, I believe he needed to hold Seattle to two runs to give the A's a reasonable chance at winning. On the other hand, I don't think he needed to go six innings because not only do the A's boast an extremely talented bullpen, the relievers were all well-rested due to Friday's postponement. Just getting through five innings may have been sufficient, or getting one or two of the outs in the sixth inning. (Side note: through the first three innings, Felix looked like he had perfect game material on Saturday. I believe 25 of his first 29 pitches went for strikes.)
In Wednesday's second game, Josh Lindblom went 4 2/3 innings and allowed two runs. Considering the circumstances, I would define this as a quality start. The bullpen was well-rested, the offense was looking sufficient against Zach McAllister and Lindblom was making a spot start.
On Monday, Scott Kazmir probably had the leeway to allow a fourth run, or even a fifth, considering Minnesota's pitching struggles. I think the six innings were an accurate measure of a quality start, given that Luke Gregerson and Jim Johnson were worn out. The combination of Fernando Abad, Ryan Cook and Dan Otero were enough to handle the last three innings, and Sean Doolittle probably could've worked if he was needed, as he threw just four pitches to get three outs on Sunday.
Consider a team like the Tigers or Angels, with a powerful offense but weak bullpen. In their cases, I would consider a quality start to be seven innings and four runs. The Tigers have built a starting rotation that can handle these circumstances. Anaheim, on the other hand, doesn't have too many inning-eaters. Tonight, Hector Santiago failed to make it out of the fifth inning. Texas' lineup and hitter-friendly environment gives the starter room to allow a fourth run on most nights. A team like the Marlins, with an anemic offense but decent bullpen, would likely need a starter to go six innings but hold the opposition to two runs.
I consider Travis Wood of the Chicago Cubs to be the poster boy of my subjective quality start system. In 2013, he lasted at least six innings and gave up no more than three runs in 24 of his 32 starts, but he finished with a record of 9-12 and the Cubs were 12-20 in games he started. Why is this? The Cubs had the third lowest-scoring offense in all of baseball and their bullpen was second-worst in the league in terms of WAR. To give the Cubs a reasonable chance to win most games, he really needed to hold the opposition to two runs and/or last seven innings. This isn't so much a knock on Wood (pun intended) as it is a knock on quality starts as well as a knock on the Cubs' inability to build a substantial lineup or bullpen. Six innings and three runs is sufficient for the average team. However, Travis Wood was pitching for a considerably below-average team and thus would have needed to go above and beyond in order to put his team in a favorable position. Wood had a solid year on the mound and would have been a valued piece on a contending team. He reached the six-inning, three-run benchmark in 17 of his first 18 starts. He also did lots of work to help his own cause. Wood made the All-Star team and even defeated Clayton Kershaw. Wood simply had the misfortune of playing for a weak team.
As for our boys in green and gold, I think on most nights, a quality start for the A's is five to six innings, with no more than three runs allowed. This can be tweaked depending on the availability of relievers as well as the strength of the opposing pitcher. For these reasons, I believe the A's have built a rotation that can handle what is being asked of them. They don't need inning-eaters, they just need to get through five or six innings and to keep the opposing offense from erupting. Billy Beane equipped the team with appropriate pieces. As much as I like Bartolo Colon and his version of the Truffle Shuffle, a pitcher like Scott Kazmir is more fit for the 2014 Oakland Athletics. He's not here to eat innings, he's here to hold the opposing offense down for five or six innings, and occasionally he'll go above and beyond that, as he did last Wednesday against the Indians. I already believed Kazmir was an improvement over Bartolo with health and age taken into consideration. Looking at the composition of Oakland's lineup and bullpen makes the decision seem even more logical. Successful teams don't need a loaded starting rotation to win, and it's tough for a successful low-payroll team to load up their starting rotation unless they draft a series of studs like Tampa Bay did. Beane pieced together a rotation that should provide his offense and bullpen with a good chance of winning each game. If the starters can survive two or three trips through the opposing lineup, the A's have a solid shot at a win on almost every occasion.