Oh, I'm sorry. I originally thought you were in a 10 team league. Yeah, with 20 teams, the FA market is really thin.
Guys I might dangle in a trade now:
Chase Headley (I think Walker has higher upside)
Russel Martin (I might be in the minority but I think his best days are behind him. But, you'd have to get a C. So...)
Edwin Encarnacion (I think his ceiling is pretty limited and you might get someone who thinks his current streak will continue.)
Jose Tabatha (the wife, the unknown age, the Yankees demoting him to single A before trading him, I'd see what you could get for him. A young catching prospect?)
Sorry I'm not more help, especially with the pitching.