Bad season preparing for next year, Keeper... ?

So I am trying to trade for a solid keeper. I joined a very active 12 team league at the beginning of this year and inherited a terrible team and have no chance of making the playoff. I have a manager interested in a couple of my players. He has Forte, Barber and Turner that I can pursue. I have Colston, Fitzgerald, E Graham, Slaton and Rodgers. Do you guys think I could get Barber for Colston and Graham. I am willing to trade on the "lower" side in order to have a quality keeper that isn't a WR. What player would you pursue if you were already building for next year?