Here's a little more food for thought on the Rams third down conversions against the Patriots last week.
One thing I speculated - and something that I think most of us were thinking - was that having Steven Jackson in the lineup might have changed some of that. And I say some because so many of the Rams third down opportunities (11 of 16) came with a lot of yards left to go, i.e. situations where the offense was less likely to use a running play.
So, using Football Outsiders offensive line stats we can get some idea of the impact Steven Jackson has. Comparing the Rams adjusted line yards with their running back yards and, more importantly, the percentage of the Rams total rushing yards extending 10 yards or more beyond the line of scrimmage (see here for more precise definitions and the full set of numbers).
The Rams have an adjusted line yards number of 3.77 yards per carry, 28th in the league. Rams running backs average 4.04 yards per carry, and 19% of their total rushing yards have come on carries of 10 yards or more past the line of scrimmage, 19th in the league. Teams, like the Rams, with better numbers/ranking on 10+ instances than adjusted line yards are more dependent on their running back than the line.
Surprise, surprise. I think here this reflects the immense level of talent (well, except for pass blocking) that Steven Jackson has, more than it does the middling quality of our offensive line.
Now, on those third-and-long it's unlikely the Rams would have run much even with Steven Jackson. But you can bet they could have made some screens or short passes over the middle and let Jackson's legs do the rest.