I know that I'm beating a dead horse here, but I believe that relatively exhaustive statistical data shows that the quality start (six innings or more, three runs or less) produces almost 70 percent winning percentage. Conversely, the non-quality start has a far more mundane and much lower winning percentage.
A reader writes that I forgot about Beckett's start. Although I was on vacation, the Box Score I read showed five innings and one run allowed, definitely an excellent start (who wouldn't take that every game?) but not by definition a quality start.
Last year when I was following this, the team with the highest percentage of quality starts (which surprised me initially) was Detroit. It usually takes some digging to find this, but maybe I'm looking in the wrong holes.
Anyway, that's my story, and I'm sticking to it. I do agree that Beckett may be the key to the season, presuming solid starting pitching at the top of the rotation with Schilling and Matsuzaka, and competitive starting pitching at the back end of the rotation.