The only one I'd consider dropping for Green at the moment is Lofton. Green will certainly break out of his slump, but his numbers won't approach the expectations a lot of people had in him before the season - losing Sheffield in the lineup hurt Green quite a bit.
If you feel Lofton will come down to earth, drop him for Green; if not, stay put. Your outfield is fantastic - you can afford to follow your instincts on this one. If it were my decision, I'd stay, watch these players closely until the waiver deadline, and see if anything happens that would influence the decison. I'd probably keep the guys you have, though.