Most NFL teams have 4 RB's and at least 1 FB, the team we played last season in the SB has 2 FB's (39 M. Hedge****, 24 R. Douglas) and 4 RB's (27 B. Jacobs, 34 D. Ward, 44 A. Bradshaw, 22 R. Droughns). Only Bradshaw plays teams, he returns. BTW, Faulk and Jordan can return for us.
No, not really. Here's what teams had on their active rosters to end last season (be it Week 17 or a playoff game). Keep in mind that a lot of these teams use the FB a lot more than the Pats do, and thus require a 2nd FB (the lack of which doesn't mean a 4th RB can be carried, since that brings less value than a 2nd FB would, unless you're running a 2 RB set instead of a 1 RB/1 FB set). Also, you might notice how some of the 3rd and 4th RBs (they're listed in depth chart order) are more kick returners than backs - like Mahe, Sproles, and Scobey.
BUF: 4 RBs (Lynch, Wright, F. Jackson, S. Williams), 2 H-Backs (Neufeld, Massaqoui)
MIA: 4 RBs (Chatman, Cobbs, Booker, Gado), 1 FB (Mauia)
NE: 2 RBs (Maroney, Faulk), 2 FBs (Evans, Eckel)
NYJ: 2 RBs (T. Jones, L. Washington), 1 H-Back (Kowalewski)
BAL: 4 RBs (McGahee, M. Smith, M. Anderson, C. Ross), 2 FBs (McClain, J. Green)
CIN: 3 RBs (R. Johnson, K. Watson, Q. Wilson), 1 FB (J. Johnson)
CLE: 3 RBs (J. Lewis, J. Wright, J. Harrison), 2 FBs (Vickers, Ali)
PIT: 3 RBs (Davenport, G. Russell, V. Haynes), 1 FB (C. Davis)
HOU: 2 RBs (Dayne, D. Walker), 2 FBs (Leach, Cook)
IND: 3 RBs (Addai, Keith, Dawson), 1 FB (Lawton)
JAC: 3 RBs (Taylor, Jones-Drew, Toefield), 2 FBs (G. Jones, M. Owens)
TEN: 3 RBs (L. White, C. Brown, C. Henry), 2 FBs (Cramer, A. Hall)
DEN: 3 RBs (T. Henry, S. Young, A. Hall), 3 FBs (C. Sapp, P. Smith, M. Bell)
KC: 2 RBs (K. Smith, J. Battle), 3 FBs (K. Wilson, Grigsby, G. Harris)
OAK: 2 RBs (Rhodes, Jordan), 2 FBs (Griffith, O. O'Neal)
SD: 3 RBs (Tomlinson, M. Turner, Sproles), 2 FBs (Pinnock, L. Neal)
DAL: 3 RBs (J. Jones, Barber, T. Thompson), 1 FB (Hoyte)
NYG: 4 RBs (Jacobs, Droughns, Bradshaw, Ware), 1 FB (Hedge****)
PHI: 4 RBs (Westbrook, Buckhalter, T. Hunt, Mahe), 1 FB (Tapeh)
WAS: 3 RBs (Portis, Betts, Cartwright), 1 H-Back (Sellers)
CHI: 2 RBs (A. Peterson, Wolfe), 2 FBs (McKie, Polite)
DET: 4 RBs (K. Jones, Duckett, T. Bell, A. Cason), 2 FBs (J. Bradley, Fitzsimmons)
GB: 3 RBs (R. Grant, Morency, B. Jackson), 2 FB (K. Hall, Kuhn)
MIN: 3 RBs (A. Peterson, C. Taylor, M. Moore), 3 FBs (T. Richardson, Dugan, Tahi)
ATL: 3 RBs (Dunn, Norwood, Snelling), 2 FBs (Mughelli, McIntyre)
CAR: 3 RBs (Foster, D. Williams, A. Haynes), 1 FB (Hoover)
NO: 4 RBs (Bush, P. Thomas, Stecker, Barclay), 1 FB (Karney)
TB: 4 RBs (Graham, Bennett, Pitman, Darby), 2 FBs (Askew, Storer)
AZ: 3 RBs (E. James, Shipp, Arrington), 2 FBs (T. Smith, Castille)
SF: 3 RBs (Gore, Hicks, M. Robinson), 2 FBs (Norris, Keasey)
SEA: 3 RBs (S. Alexander, M. Morris, Scobey), 2 FBs (Weaver, Kirtman)
STL: 3 RBs (Jackson, A. Pittman, Alexis), 2 FBs (Leonard, R. Owens)