One of the lines of thinking this offseasoincluded. is that Dallas' offensive line can make virtually any running back successful. So I got to thinking about the validity of that statement and it took me back to 1993.
The reason for that is it was Emmitt Smith's best year behind a line that some use as an excuse to dismiss him in conversations about the greatest backs ever. It was the only year he averaged more than 5 yards per carry (5.3) in his career and he won NFL MVP.
He also held out that preseason for more money, which left Dallas opening the season with Derrick Lassic at running back. Lassic averaged 3.8 yards per carry overall as the starter, but he did open the season with a 4.7 game and averaged 4.3 in this third and final game in that role. (Emmitt didn't start that third game, but averaged 5.6 yards on 8 carries in it.)
So there was a 1.5-yard drop-off per carry compared to Smith in the starting role. In the game where Lassic got his most carries (19), he also had his worst average (2.7). He also had two fumbles in that game and lost one as Dallas lost two of its first three games.
Dallas only lost two more games that season. (Smith did have four games out of 14 where he averaged less than 4.2 yards per carry.)
However, this is only a small sample to look at ... so knowing that DeMarco Murray missed a lot of games his first two seasons (only starting about half of them), I thought I'd also look at his numbers compared to the others who started.
In 2011, Murray started seven games and averaged 5.5 YPC. His per-game average was less than 4.0 in 2 of his 7 games. Dallas was 4-3 in games he started that year.
Felix Jones started eight games that season and averaged 4.1 in those games (almost a yard and a half per carry less than Murray as a starter). He averaged less than 4.0 in 5 of 8 games (2.6, 2.8, 3.6, 1.7, 2.7). He did have two 100-yard games as a starter (with 8.2 and 4.9 averages in those games).
Tashard Choice started the other game and averaged 4.0, but only had 2 carries for 8 yards.
Dallas was 4-5 in games started by someone other than Murray.
The next year, Murray averaged 4.1, but less than 4.0 in 6 of 10 starts. Dallas was 5-5 in the games he started, and 3-3 in the games started by Jones.
Jones averaged a full yard less (3.1) in 6 starts and less than 4 yards per carry in 4 of 6 starts (2.9, 1.5, 4.3, 4.4, 3.1, 2.3).
So, not considering any other factors, this shows that there is at least a yard to a 1.5-yard drop-off from a quality back to an average/below-average one behind Dallas' lines. Obviously, the line Dallas had this year was better than the ones it had in 2011 and 2012, but Murray's average was 4.7 behind that line.
If we get a similar drop-off from Murray than the combined backs will averaged around 3.7 per carry at best. Of course, we don't know if who we put out there will be better or worse than Murray, but I do think the evidence shows that you can't put just anyone out there and expect the line to make up that much of a difference.
