Just when I was wondering why the Pirates hadn't asked about any third basemen, here's one. Jon Morosi tweets that the Pirates are one of several teams to have asked about Ian Stewart of the Rockies. The only position Stewart has played since 2009 has been third base, so he would be a Pedro Alvarez contingency plan and a bench bat, and that's about it. He's not much of a starter unless he takes a step forward (which isn't totally out of the question, since he'll be 27 next year), but if Alvarez flops completely, Stewart looks better than the Pirates' other alternatives, assuming his health holds up. He'd presumably be a bench player if Alvarez won the starting job (as we all hope he will) and produced.
Stewart made about $2.3 million in his first year of arbitration in 2011. Since he was terrible and/or injured for pretty much all of 2011, he wouldn't get a huge raise on that this year. Still, I wouldn't be willing to give up a whole lot for him, since he's not worth much more than his salary.
The Rockies appear likely to trade him.