Three different teams last year didn't have a 500-yard rusher - Arizona, Green Bay and Jacksonville. That's rare (I'm not sure that it's ever happened to three teams in the same season before).
In the last 10 years, only seven other teams made it through a season without at least getting somebody halfway to the 1,000-yard mark.
LEADING RUSHERS UNDER 500 YARDS (2002-)
Att Yds Year
112 425 2004 Amos Zereoue (Oak.)
157 451 2005 Marcel Shipp (Ariz.)
68 343 2008 Peyton Hillis (Den.)
124 494 2009 Clinton Portis (Wash.)
131 437 2009 Steve Slaton (Hou.)
129 497 2010 Donald Brown (Ind.)
84 390 2011 Jahvid Best (Det.)
135 464 2012 Alex Green (G.B.)
86 414 2012 Maurice Jones-Drew (Jac.)
111 357 2012 LaRod Stephens-Howling (Ariz.)
^aEUR"Ian Allan