The terms "sixth starter" and "rotational depth" are bandied about quite a bit, but what level of performance should we really be expecting from players mentioned in these groups? It certainly isn't league average production, though every fan hopes that the pitcher will suddenly find himself and the team will have another asset to develop.
I see sixth starter/rotational depth guys as fitting into one of three archetypes -- the failed blue chip prospect, the scrapheap veteran, and the fringe prospect. Okay, so I made those designations up so that one would fit each guy I'm reviewing.
Unfortunately for the Rockies, their failed blue chip prospect was a player that they selected 2nd overall in the 2006 draft, Greg Reynolds. The 25 year-old righty was projected as a polished mid-rotation starter when Colorado took him, but he's been a pretty colossal bust as a pro. A large part of the reason for this is injuries (Reynolds made the big leagues in 2008), but the fact is that the Rockies made a pretty bad misstep in picking Reynolds.
The best thing that can be said about Reynolds' performance for the 2011 Colorado Rockies is that he was undefeated (3-0) in 3 starts and 10 bullpen appearances...but his 6.19 ERA, 1.56 WHIP, and 5.06 K/9 rating in 32 IP suggest that he was pretty darn lucky in getting there. Despite the W-L results, Reynolds wasn't a MLB caliber pitcher last year...and the fact that he threw 32 MLB innings is an indication that Colorado's rotation was in pretty desparate straits. I mean, I know that the PCL is a hitter's league, but in 109 IP in AAA Reynolds had a 6.81 ERA and a 1.75 WHIP. Yikes.
Colorado's scrapheap veteran in 2011 was clearly Kevin Millwood, the 36 year-old righty who had spent most of the year in the minors before Colorado picked him up on the cheap in August. Millwood had already had a pretty distinguished career and had been a good pitcher fairly recently (he had 3.4 rWAR in 2009), so there was some more hope with Millwood than with Reynolds.
Millwood made 9 starts for Colorado, went 4-3 with a 3.98 ERA, and generally acquitted himself with style and aplomb at the plate, swatting 2 HRs in 23 PAs. He was a league average starter, in other words...and in this league, there's considerable value in that. I hope that Colorado is able to bring him back cheaply as an option for the 2012 rotation...if nothing else, Millwood has demonstrated the ability to eat lots of innings (at least 120 IP every year from 1998 to 2010, most seasons over 160).
Clayton Mortensen, acquired for Ethan Hollingsworth last offseason, was never a highly regarded prospect despite his sandwich pick pedigree (though he was in the 2nd Holliday trade), but he was considered to be the consummate sixth starter/rotational depth guy coming into 2011.
Even so, the 26 year-old soft tossing righty was able to throw 58.1 innings and go 2-4 for the Rockies, split between the rotation and the bullpen (again, Colorado's pitching was a bit of a wreck last year). His 3.86 ERA and .257 BABIP against belies his pretty bad peripherals (4.63 K/9, 3.70 BB/9, 5.34 FIP). He was reasonably effective in early action, but the law of averages caught up to him a little bit near the end of his MLB stint.
In other words, Mortensen was pretty lucky in 2011 and still graded out as a replacement level pitcher (by fWAR) or an okay pitcher on a rate basis (by rWAR). Either way, he's not a guy that figures heavily in Colorado's rotation plans going forward.
The fact that pitchers like Greg Reynolds and Clayton Mortensen got significant major league pitching opportunities last year is the reason why acquiring higher upside (than them) players like Tyler Chatwood and Kevin Slowey make a ton of sense for this team. We don't want 2011 to happen again.