John Dreker caught Neal Huntington's interview today on MLB Network, in which Huntington spoke about what the Pirates plan to do if Russell Martin leaves:
We are going to do everything we can that makes sense. It’s not just about retaining one player, it’s about building a championship club and sometimes the small markets have to let players go and sometimes large markets let players go because other teams are willing to pay more. If that happens, we will regroup, we will go acquire the best available catcher we can and then reallocate those resources to try to make the rest of our club stronger and try to get back to the postseason in 2015.
As Tim notes, Huntington seems to be suggesting the Pirates won't go with Chris Stewart and Tony Sanchez as their catcher combo if Martin departs. I'm not sure there are any legitimate upgrades over Stewart on the free agent market, so that might mean the Pirates will think about a trade. Actually, upgrading on Chris Stewart is more difficult than you might think. Yasmani Grandal of the Padres and Jason Castro of the Astros could be two possibilities; perhaps Welington Castillo of the Cubs could be another one, if Martin signs with Chicago.