Unless the other guy has no RB2 at all, I wouldn't do that if I were him. Jackson is banged up. I think Hillis is actually OK as a low end RB2/flex play. Knox is a decent WR. But for the other guy to give up CJ, he would need to be hurting at RB and WR some.
12 Team League. We start 2 QBs and get .5 PPR, otherwise standard scoring
QBs: Stafford, Fitzpatrick, Collins
RBs: Charles, Mendenhall, Best, Starks, Carter, Karim
WRs: D. Jackson, Marshall, S. Smith, Green,
TE: Hernandez, Cook