There are three guys definitely returning, and Pittsburgh should look outside the organization for more help. There's no trade bait worth trading so that means signing two free agents. Any major league team needs a legitimate (non-Morton) starter every time out.
RETURNING
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Ross Ohlendorf went 1-11, 4.07 in 2010. He pitched well but was probably the most unlucky starter in the majors as he got no run support and was injured three different times including two DL trips. The injuries are worrisome, but this was Ross's second straight solid season and there's no reason not to have him in the 2011 rotation.
Paul Maholm went 9-15, 5.10 in 2010 which was his worst year so far. Overall his numbers are a respectable 47-59, 4.48 in six seasons. The Pirates' defense was much worse in 2010 than in previous years which may partially explain his off year. Nevertheless, he's going to have to be better in 2011. Maholm is set to earn $5.75 million next year, so the best thing to do is chalk up 2010 as an off year and hope for better results.
OUT OF THE ROTATION
Pitching their way out of a job were Charlie Morton (2-12, 7.57) and Zach Duke (8-15, 5.72). Unquestionably Morton has good stuff, but he proved in 2010 that he is just too unreliable to pitch in the major leagues. People have argued this point but it is unfathomable to me that anyone wants to bring him back. Duke was too hittable to be worth going to arbitration with and should be non-tendered.
Jeff Karstens (3-10, 4.92) and Brian Burres (4-5, 4.99) can start and relieve and pitch in AAA and the majors, but simply aren't good enough to be Top 5 guys. They'll be valuable when someone gets hurt but are basically below average pitchers. They shouldn't be in the five-man rotation on Opening Day.
Daniel McCutchen (2-5, 6.12) and Brad Lincoln (1-4, 6.66) proved that they are AAA pitchers.
MY FREE AGENT PICKS
The Pirates aren't going to sign Cliff Lee, but pitching is unpredictable and every year there are teams that get a great performance out of guys who sign for between $2 and $4 million. Here are the two guys who I would round out the rotation with:
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Kevin Correia (10-10, 5.40) was hit hard in 2010 after a great 2009 year. Correia posted a sub-4.00 ERA in three of four previous seasons and has strikeout ability and durability. He'll only be 30, and all indications are that he had terrible luck in 2010. If he continues to strike out seven batters per nine innings with good control and durability, he's well worth the $2 million he'll sign for.