I'd go AJ Green. TWO straight solid years, more proven. WRs don't take the beating a RB does so you will have him for more years as an anchor on your team. I have the muscle hamster this year, but if I had to choose between keeping the two, I would keep Green.
14 Team 5 pts per 5 receptions
QB, 2RBs, 3WRs, TE, FLEX(WR/TE), K, DST
QB- Romo, Freeman, Manuel
RB- Sproles, J Bell, Bernard, W McGahee
WR - Megatron, D Bryant, V Brown, A Jeffery, R Randle, P Harvin(IR)
TE- J Graham, Sudfeld
DST - Dallas