According to an article on sportsillustrated.com, the rise of the spread offense, the increasingly pass-happy nature of the NFL, and the success of later-drafted running backs have all led to a decline in the draft stock of running backs across the board. What is an elite running back to do? Easy. Go to Alabama.
I'm not going to repost the whole article. You can read it here: http://sportsillustrated.cnn.com/2011/writers/don_banks/04/05/nfl-draft-running-backs/index.html?eref=sihp. I will, however, repost a couple of telling excerpts.
As is the case with several other positions, namely at quarterback, the rise of the spread offense in the collegiate ranks has made it more difficult to accurately assess running backs for NFL potential, league sources told me. That has added a level of projection to shopping for runners in the first round, with some rushers putting skills sets on tape that don't always translate to the NFL game.
"A lot of the recent trend has to do with the level of specialization at both the NFL and the college level,'' said former Vikings running back Robert Smith, a 1993 first-round pick who is now a college football analyst for ESPN. "There are so many spread offenses in college that you might not even get a sense for a guy's pass-blocking, because it's a different kind of pass-blocking in the NFL.
"Even how they run the ball is different in the spread, out of so many passing sets instead of closer to the line in a traditional pro-set offense. It makes it difficult to project how those guys will transition into the league. There just aren't a whole lot of guys like Mark Ingram coming out of the college game, guys who have run and blocked out of a pro-set formation.'' [emphasis added.]
"I know this much, when you watch Ingram's sophomore tape, he was a beast,'' the NFL club personnel man said. "But he was hurt a little bit last season. It's conceivable that some teams may like [Illinois running back Mikel] Leshoure over Ingram, but we don't have it that way. If you take Ingram, and you get the runner he was in 2009, you might be getting a real value. Because you've seen him do it and know what you're getting.'' [emphasis added.]