The aberration was 2009. It was the first time he averaged 4.0 yards or more per rush since 2006. It was his highest yardage total and yards rushing per game. In 2010, Benson fell back to his 3.7 yard/rush career average and (roughly) 60-yard average in 2008 and 2010. There's always mitigating factors when examining a certain players of a certain position in a sport that personifies team. One more block by Nate Livings, a more threatening passing game, a stronger defense that allowed the Bengals to take the lead earlier in games that otherwise knocked Benson's importance out of the ballpark far too early in these 12 losses.
According to Pro Football Focus' Andy Clay, if you "normalized" the Bengals schedule to reflect average 2010 opponents, Cedric Benson's variation from actual to normalized production increases by 0.13 yards/rush. My god, what's the big deal about 0.13 yards/rush, you ask when averaging the team's strength of schedule? Not much actually. Besides being the fourth best improvement, Benson still produced one of the league's lower yards/rush average amongst NFL feature backs.
Factor in the little known realization that Benson plays four games against two annually strong rush defenses (Baltimore and Pittsburgh), and what really improves overall is Benson's touchdown rate. I know this is all statistical mumble jumble to some of you and may not interest you in the slightest. To others it may just strengthen the belief that the Bengals need to bring Benson back; hopefully with another 2-3 year contract that's manageable enough not to cripple the team.