Meet Bob. Bob links to Rob. Rob talks about quality starts. Meet Ken. Ken agrees with Rob: the "quality start" is a pretty good stat. It's not perfect, by any means, but it does explain things sometimes.
It certainly explains why the A's just got swept in Minnesota. The A's didn't get anything even resembling a quality start against the Twins.
Last year, the A's quality start percentage nearly matched their winning percentage: they got 90 quality starts, and won 88 games.
This year, the A's only have three quality starts out of ten. They're 3-0 in their games with quality starts, and 2-5 without them.
I certainly expect the A's to get a lot closer to the 55% quality start percentage they had last year than the 30% they've put up in 2006. So while falling back to .500 is disheartening, there's no reason to panic about a 10-game stretch of .500 ball. These things happen. The pitching will come around, and things will get better.