I wouldn't handcuff Michael Turner, especially in a PPR league. His value is down in PPR leagues because he has stone hands and is never targeted. He's one of the backs where the handcuff does absolutely nothing to warrant having a bench spot, and as you say, it's not even clear who the handcuff should be.
This is very similar to handcuffing Steven Jackson with I don't even know who backs him up. You should have another team's RB on your bench who would start ahead of Snelling/Norwood in the event that Turner gets injured.
12 team H2H league, standard scoring, no PPR. QB: Cutler, Kitna RB: All Day AP, CJ2K, F.Jax, R.Brown, S. Greene, Dixon WR: G. Jennings, Roy Williams, M. Williams (sea) TE: J. Tamme Def: Denver K: Hartley, Carpenter