I love how people love to use the overall team statistics of the opponent with zero context for their argument. Oakland has a terribly ranked run defense for the season...but lets look at some of the individual performances against the raiders this year...
T. Richardson: 20 carries 72 yards 3.6
R. Rice: 13 for 35 2.7
M. Turner: 11 for 33 3.3
R. Jennings/MJD: 22 for 50 2.3
Charles/Hillis: 9 for 27 3
They gave up huge busted games to Bush and Doug Martin (Martins 250 yards really skew the stats). Oakland is bad, but lets not pretend that they don't have the ability to clamp down on a runner, pro bowl runners as a matter of fact.