MLB released its list of arbitration eligible players today. You can find the entire list here. For the Pirates, Zach Duke, Ronny Cedeno, Matt Capps, and Jeff Karstens all qualified, with Karstens just barely making the service-time cut. Because Karstens is only in his first year of arbitration and will thus remain fairly cheap, it's probably a slam dunk that the Pirates will tender offers to their four guys.
On the other hand, MLBTradeRumors guesses that about 40 guys from this list will be non-tendered, probably most of them from the top half of it. Most of those 40 will be chaff, but there are usually a few diamonds in the rough that sneak out. Contracts have to be tendered by December 12th, so until then speculation about non-tenders is just that.