According to Baseball Prospectus, the A's had the second best rotation in the AL last year. Second only to the Angels...

It's their stat of the day on their front page.

http://www.baseballprospectus.com/

Top 5 2005 AL Rotations, by SNLVAR
Team VORP SNLVA SNLVAR
LA Angels of Anaheim 195.6 10.4 25.9
Oakland Athletics 185.7 9.9 25.4
Chicago White Sox 209.2 9.2 24.4
Minnesota Twins 177.2 6.1 21.5
Cleveland Indians 150.0 5.7 20.9

It's sorted by SNLVAR, which is:

like SNLVA, but comparing to replacement level, rather than average. Replacement level is now being computed the same way in SNVA and in VORP (using the formulas from Keith Woolner's BP 2002 article).

so what's SNLVA?

Support Neutral Lineup-adjusted Value Added - like SNVA, but also adjusted for the MLVr of each batter the pitcher faced.

ok, then, and SNVA would be...?

Support Neutral Value Added - wins above average added by the pitcher's performance.

Sometimes acronyms make my head hurt. Here's an older article about SNVA.