So far, I've been fairly impressed by Luke Hochevar's first 91 MLB innings pitched.  He hasn't been dominant, but he's pitched at the level of a solid #2 starting pitcher.  What I find interesting is that he's apparently a pretty extreme sinkerballer.  As Rany recently pointed out,

Coming into the season, Luke Hochevar projected to be a league-average starter, and that’s exactly what he’s been: in 13 starts, he’s 5-5 with a 4.60 ERA, which is as average as they come. But league-average pitchers come in all shapes and sizes, and the particular shape of Hochevar’s performance has surprised me. Specifically, I had no idea back in April that he was such a groundball pitcher. The talk about Hochevar was that he had four pitches that graded out at average or better, not that he had an outstanding sinker. Today, we know better.

He later went on to say,

Counting tonight’s performance, Hochevar has allowed 140 groundballs and just 71 flyballs this season, a ratio of 1.97 which would rank him 11thamong major league starters (min: 60 IP) this season. The three guys directly above him on the list are Greg Maddux, Chien-Ming Wang, and his opposing starter tonight, Aaron Cook. That’s excellent company for a starter to be in, particular a starter who doesn’t have a huge strikeout rate.We’ve come to grips with the fact that Hochevar won’t be an ace befitting his draft status, but he seems to be on the career track of a guy like Cook or Derek Lowe, a guy who can give you 200 innings a season and keep his ERA a little below league average. There are a lot of #1 overall picks who would have loved to have a career like that.

Sinkerballers tend to have a unique statistical profile.  They have high a high ground ball percentage, low fly ball percentage and a pretty good ERA despite their often low strikeout rates.  Their ERA's are typically lower than their FIP because their ability to induce poor contact, and particularly groundballs, allows them to out-perform their strikeout and walk rates.  

Before I get into a deeper analysis of Hochevar's stats, let me say that all of the caveats about small sample size apply.  He's had 91 MLB innings pitched.  That isn't enough to draw conclusions about him going forward.  All we can do is analyze what he's done so far.

Here are the career stats of some noted sinkerballers (this is not an exhaustive list.  These are meant to be exemplars of starting pitchers who rely on their sinkers, get a lot of groundballs, and have managed to be anywhere from #1 to #3 starting pitchers throughout their careers..  There are some worse pitchers like Jason Marquis and Braden Looper and some good pitchers like D. Lowe and R. Halladay who are not on the list.):

That's a lot of data to digest.  I think Hochevar's profile is consistent with the rest of the sinkerballers/extreme groundball pitchers on that list.  Clearly he needs to work on his walk rate and flyball rate.

The way I ordered the list was Hochevar at the top for comparison purposes, and then in roughly ascending order of overall pitcher quality from Cook to Webb.  Right now, only halfway through his rookie season, I think Hochevar sits comfortably in the group of Cook, Garland and Westbrook, all capable #3 starters.  With a bit of improvement in his walk rate and flyball rate, he could easily move up into the #2 SP group with Carmona and Wang.

Hochevar has a long career in front of him and, as I said, it could go in any direction.  But if he keeps pitching like this, with the kind of development and improvement that you'd expect from a 24-year-old pitcher, I think it's safe to say that the Royals have a pretty good #2-#3 starter for a long time to come.