I'll say 4th Round. I'm not sure if RBs are in high demand like in the past few years. I see the #1 RB going about Mid 1st Round (C.J. Spiller). With Tate, if he runs a great 40 (4.4-4.45) then he'll definitely go 4th Round or possibly 3rd Round. Gone is the day that NFL teams have only one good RB, now they're wanting a Ground Pounder, a Bolt of Lightning and a mixture of the two. With Tate, IMO, he's a mixture of the two.
This year, DTs and OL are in somewhat high demand.
DTs (1st Round to mid 2nd Round)
Suh (Neb)
McCoy (OU)
Williams (UT)
Odrick (PSU)
Price (UCLA)
Cody...probably 4th Round (depending on how well he moves and if he decides to drop his Agent before the Draft. He's using the same Agent that Andre Smith had before the Draft, the one that told him to run without a shirt and didn't tell anyone that his client was leaving the Combine)
OL (1st Round to mid 2nd Round)
Okung (OKSt)
Bulaga (Iowa)
Williams (OU)
Davis (Rutgers)
Iupati (Idaho)