Davies is the only one of the four that pitched more than 130 innings in 2010 (183.2) and his resulting 78 ERA+ pretty much affirms that he is who we thought he was (meaning not very good). Again, his being the #2 starter may be a grim portent of things to come. I tweeted a few days ago that whoever wins the fifth starter will have a higher ERA+ than both Davies and SOS. To clarify that point further I mean whoever the fifth starter is, whether it's a veteran brought in to be the #1 guy or one of the in house candidates (more on them later). I honestly believe this to be true. Davies has pitched over 700 innings in his career and his ERA+ has been on the south side of 90 in all of them but one, his fluke 2008 season (108). Sean O'Sullivan just isn't very good and frankly wasn't very good in the upper minors, he put up a 5.08 ERA in 154 AAA innings. How he found his way into a major league rotation is beyond me.
I wouldn't be surprised to see Hochevar and Mazzaro approach or transcend ERA+'s of 100, I know they both have plenty of doubters but I'm not one of them. Hochevar had career best's in ERA, WHIP, and H/9 in 2010 - like with Gordon I still believe he will justify being a first round pick (he probably will never justify being #1 overall but few pitchers do). Mazzaro is coming off a 97 ERA+ season, Oakland's defense is credited with some of that so KC improving their up the middle defense with the Greinke trade should make people feel better about his acquisition.
According to Moore the fifth starter candidates are Everett Teaford, Aaron Crow, and Danny Duffy. Given Moore's reluctance to rush prospects I think Teaford emerges as the winner. Crow and Duffy are considered important pieces of the future but have combined for less than 500 minor league innings, zero at AAA. Teaford, on the other hand, has 590 innings under his belt. Granted just 4 at the AAA level but I don't think promoting a 26 year old to the majors after a good AA season (14-3 3.36 ERA) would be considered rushing. So am I saying that Teaford will outpitch Davies and SOS? Why yes, yes I am.
Now should Moore go the veteran route I think we still end up seeing Teaford in the rotation if/when SOS pitches his way out of it (May 1st?). Crow, I think, will find his way into the rotation in the season's second half. I also think he will only get so many innings to establish himself before being sent to the bullpen, which is to say he's not getting the Hochevar treatment.
In my vision of a perfect world the rotation would consist of Hochevar, Tejeda, Mazzaro, Davies, and Teaford with a hopefully improved Crow replacing Davies by the all-star break. Tejeda is not joining the rotation though and the sooner I accept that the happier I'll be. Right?