Need a RB for depth. Bush, Jacobs, or Tolbert?

My Roster (standard):

P. Manning
R. Mendenhall
M. Forte
B. Marshall
P. Garcon
S. Johnson
A. Hernandez
D. Carpenter
N.O Defense (Waiver permitting)

Bench:
J. Flacco
R. Torain (BYE)
V. Jackson
S. Rice
R. Meachem
S. Moss (BYE)

This is all assuming I do not pick Blount off of waivers tomorrow. I have the 7th pick out of a 10 man league so I'm not hopeful. Currently sitting in 4th place overall so I want some RB depth down the stretch. The other guys in my league won't trade either because they don't understand fair deals or are too scared to pull the trigger so waivers are my only hope.

All three of these guys are backups on RB by committee teams and each have their strengths so I'm having a hard time making a decision. I'm leaning towards Jacobs because he's just as good on the goal line as Tolbert but he has more of an ability to really break through and pick up good yards midfield. Also, the Giants are more likely to use Jacobs midfield as well as the goal line as SD is with Tolbert. The only reason I'm considering Bush is because Oakland needs to give Mcfadden a break often and I'm not convinced Mcfadden is going to finish this season without another injury.

Also, I'll be dropping Flacco. I just haven't dropped him yet after Peyton was on bye.

Thanks