The A's "Rotation"

Marc Hulet at Fangraphs has a pair of posts dealing with fifth starters.  In the first, he makes the argument that there's no such thing as a fifth starter, finding that in 2009 only the Cubs and Rockies had "fifth starters" that made more than 24 starts.  He then suggests a new approach to filling out the back end of the rotation.  Hulet suggests that teams use:

1. A long reliever who would serve as the seventh arm in the ‘pen and be expected to make eight to 10 starts on the year. Ideally, this would be a proven veteran who could stick at the MLB level all season.
2. A pitching prospect that projects to be a fringe No. 3 or 4 with two or three minor league options remaining. He would be introduced to the Majors in this low-pressure role over the next two to three seasons before officially (hopefully) graduating to the role of a reliable third or fourth starter. In this role, the pitcher would need to make about 10 starts at the MLB level each season.
3. A minor league “veteran” pitcher (somewhere in the 25-30 year old range) who has been unable to stick in the Majors – and still has at least one minor league option left – and can be relied on to make at least five starts on the season.

I agree that people talk about fifth starters (or Number 1 or Number 2 or Number 3 or Number 4 starters) in a confused manner.  At first glance I'm not sure I agree with this solution to the fifth starter problem.  To me, it looks like you're wasting three roster spots on pitchers who are good bets to be around replacement-level.  That being said, the idea that there really is no such thing as a fifth starter got me thinking (some more) about the A's rotation. 
The A's have at least eight pitchers who are probably major league caliber starters (Sheets, Anderson, Duchscherer, Braden, Cahill, Outman, Gonzalez, and Mazzaro).  The A's also have a number of other pitchers who are probably around replacement level right now, some with the chance to be better in the future (Jason Jennings, Brett Tomko, Clayton Mortensen, Tyson Ross, James Simmons).  None of these pitchers are good bets to make 30 starts this year, either because of health issues, youth, or potential ineffectiveness (or a combination of the three).

What we really need to consider is this:  The A's need to find pitchers to start 162 (regular season) games this year.  How should those be split up?  Ideally the best pitcher would get the most starts, the second best pitcher will get the second most starts, the third best pitcher gets the third most starts and so on.  The best way, then, to think about a team's rotation is not the top five starting pitchers, but all the starters who may end up starting a game, ranked from best to worst.  The A's "rotation" would look something like this:

1.  Brett Anderson
2.  Ben Sheets
3.  Justin Duchscherer
4.  Dallas Braden
5.  Trevor Cahill
6.  Josh Outman
7.  Gio Gonzalez
8.  Vin Mazzaro
9.  Jason Jennings
10.  Brett Tomko
11.  Clayton Mortensen
12.  James Simmons
13.  Tyson Ross

(This is just a rough ranking of these players, I could see an argument for each pitcher ranked 2-3 spots higher or lower.)

Obviously, when judging the strength of a team's rotation you wouldn't want to put a lot of weight on the quality of the 13th man.  But guys six through eight or nine are somewhat important.  To get a really good read on the rotation you'd probably also want to guess how many starts each guy will make over the course of the year.  I've made those estimates for the A's this year below.(Warning, ridiculously wild guesses to follow.)

Anderson - 30
Sheets - 18
Duchscherer - 14
Braden - 24
Cahill - 24
Outman - 6
Gonzalez - 22
Mazzaro - 15

Jennings - 5
Others - 4

Obviously these numbers will be wrong.  Sheets and Duke could end up making 40 starts between them (or 10).  But I think this paints a better picture of the A's pitching staff than a traditional look at the 5-man rotation.  Despite all the words I wrote last week about who will break camp with the A's, it's important to remember that the Opening Day roster will undergo a lot of changes over the course of the season, and the starting rotation is where a lot of those changes will take place.