In the past 12 months, I've almost certainly written more about Ross Ohlendorf than I've written about any other Pirate. Ohlendorf's a smart guy and Joe Kerrigan is a smart guy and their approach to Ohlendorf's first full big league season as a starter was very interesting to me. At first, Ohlendorf couldn't find the velocity on his fastball that he had in the minors or as a Yankee reliever. He and Kerrigan leaned on heavily on his sinker then. The results were mixed at best. In his first 20 starts in 2009, he had a 4.51 ERA, averaged fewer than five strikeouts per nine innings, and his groundball ratio was a middling 1.23. Late in the season he found his fastball and his ERA dipped way down to 2.75 in those final nine starts with his strikeouts jumping to nearly seven per nine, though his homers jumped as well.
The final result was that Ohlendorf's ERA ended below 4.00. As a result of that awesome finish, there are some Pirate fans that think that he's an ace waiting to happen and the only thing that can prevent him from claiming that title is a "curse" that prevents Pirate pitchers from have two good seasons in a row. But his peripherals never matched his ERA (see this post for more, keep this link and the first link handy because I'm going to reference both of these posts quite a bit) and so there are just as many people who expect him to regress back towards his FIP and xFIP numbers from 2009, which are not good. If this happens, the first group will yell "CURSE!" and I'll write another long post expounding on the predictive values of advanced pitching metrics. It's also possible that Ohlendorf will pitch better in 2010, but the defense will be worse and his numbers will take a dip and people will yell, "CURSE!" anyways, at which point I'll probably just get a headache and roll my eyes and shake my fist at whoever I feel is most responsible (Ronny Cedeno, Garrett Jones, Jeff Clement, Pedro Alvarez, and future second baseman Andy LaRoche seem to be solid potential candidates here).
None of this goes any ways towards answering the implicit question here, which is "Will Ross Ohlendorf continue pitching well after the way he ended 2009, or will he be claimed by the regression that advanced pitching metrics see for him?" The answer isn't immediately apparent to me because of the changes Ohlendorf underwent throughout the season last year, which I think still makes him a bit hard to peg for 2010.
What I do know is this; Ohlendorf's route to any sort of success lies in maintaining his fastball velocity somewhere between 92 and 94 mph and offsetting it with his slider, which was a very good pitch last year. If he can't find that velocity and he's living between 90 and 92 and trying to throw more of a sinking fastball, he's going to have a bad year. Doing a quick and informal survey using Joe Lefkowitz's PitchFX tool, I looked at 5,000 pitches from righties thrown between 90 and 92 mph and 92 and 94 mph in 2009 (the great majority of which were fastballs, though a few sliders were mixed into mostly the first group, which is why this survey is being defined as "quick and informal"). The swing-and-miss rate of the slower group is around 5% while the upper group is around 7%. That matches with Ohlendorf's own personal strikeout jump when he ramped his fastball up at the end of the year last year.
That's not all he needs for succes, though. As noted in my earlier post (link, again for good measure), Ohlendorf's homer rate jumped to 1.5/9 innings when he increased his fastball last year. It's a pretty small sample size, but if he's giving homers up at that rate for the season it won't matter how many guys he's striking out. He's got to keep things closer to his minor league homer rate of 0.7/9 innings to really have success. I think Ohlendorf is capable of this; his GB/FB ratio actually improved (first link!) in those last nine starts at the end of the season and so his homer problem could've been a bit of a sample size artifact.
Boiled down, this is a fancy way of saying, "Ohlendorf needs to throw hard, miss bats, and keep the ball in the park," which is more or less exactly what every pitcher is trying to do. Ohlendorf has done all three of those things at various points and so the question for him now, as it is for so many pitchers, is whether he can put it all together for an extended period of time.
In terms of his real potential, he'll need to pitch even better than he did down the stretch last year if he wants to be a true "ace." At the age of 27, that seems unlikely. More than likely his ceiling is a decent middle-rotation guy. That's way more than anyone thought we got when the Nady trade went down a year and a half ago, even if his great finish last year raised some people's expectations much higher.