Honestly I don't think it's worth it unless you're getting somebody with really high upside like Eric Bledsoe. But we're not getting him unless we trade Pierce or Garnett.
Anyway, I think the 4 guard rotation the Celtics have got right now is good enough for them to get by the rest of the season, considering the revised goals they ought to have now that Rondo is injured. There's no sense leveraging future assets for the sake of being a bit more competitive this season.