I'm going to keep my summary here pretty brief, but here's a few comments/things I have noticed.
The A's have the most balanced rotation in the division. While I identified major issues in Texas (Colby Lewis) and Seattle (Ian Snell) and a minor problem in LA (Joe Saunders), the A's five starters all graded out B or above.
This changes considerably if the team starts Trevor Cahill (C-) or Vince Mazzaro (D+) over Gio Gonzalez (B+), but I'm confident that the sabermetrically-minded A's will recognize that Gonzalez is far superior to Cahill or Mazzaro at this point.
The Mariners have the best top of the rotation. Sure, the A's are balanced, but with Felix Hernandez and Cliff Lee, Seattle is the only team with two starters rated A- or better. A third, Erik Bedard, may suit up behind Hernandez and Lee later in the year, although his injuries tend to take awhile to heal up.
If I weren't so pessimistic about Snell, my Mariners projection would blow the other three teams away.
The projected fifth starters look surprisingly solid. Derek Holland (B), Joel Pineiro (A-), Gio Gonzalez (B+), and Doug Fister (B-) are all quite solid pitchers, and I rated Holland and Pineiro higher than any other pitcher in their rotations. That's not to say the rotations are great one through five—I already mentioned Snell and Lewis—but instead, it says two things:
1.) The teams better make sure they all start—Holland, Gonzalez, and Fister aren't guaranteed rotation slots.
2.) Expect some surprise contributions from the fifth starters.
Texas' starters pale in comparison to the other three teams . This isn't meant to say "TEXAS PITCHING SUCKS!" It doesn't. But there are two issues.
The first is my utter pessimism for Lewis.
The second is the lack of an ace. Rich Harden, the two-pitch pitcher in Arlington, just isn't going to cut it at the top of a rotation, healthy or not. Scott Feldman's a great story, and a solid pitcher, but also not an ace. Tommy Hunter is a solid pitcher as well, but he doesn't miss bats nearly enough to belong anywhere near the top of a rotation.
The Rangers have three hopes to get a No. 1-quality pitcher this year. They are:
1.) Have Harden start throwing the split and slider again and hope he stays healthy (This is shockingly unlikely).
2.) A Holland breakout larger than the one I've predicted (possible, but not very likely).
3.) Moving Neftali Feliz into the rotation and hoping he dominates like he did in relief (Joba Chamberlain has illustrated the chance of this happening quite vividly. Even if Feliz can pitch at an ace level as a starter, they'll need to limit his innings down the stretch, which would be a huge issue if the team contends).
Texas should get solid pitching from four of its starters, and if Colby Lewis struggles as much as I think he will, he either won't make the rotation to begin with or get kicked out for a C/C+ arm like Matt Harrison in short order. I just don't see a sub-3.90 ERA from any of these guys, and every other team has at least two pitchers that are likely to top that mark.