WSJ:

Alabama running back Trent Richardson has been anointed by former Colts general managers Bill Polian as perhaps the top prospect in this week’s NFL draft. But if current GMs know what’s good for them, they’ll wait awhile before taking Richardson—or any back.
In recent years, drafting a running back in the first round hasn’t been a worthwhile investment at all. Since 2002, 28 backs have been selected in the first round. Less than a third have ever made a Pro Bowl; on average, they gain a so-so 730 yards per season.
And yet, Richardson isn’t expected to slide past the 10th pick. Most experts expect him to go in the top five. In the past 10 drafts, only five backs have been this prized: Ronnie Brown, Reggie Bush, Cedric Benson, Darren McFadden and Cadillac Williams. This quintet has averaged just 663 yards per season, and only McFadden remains on his original team (the Raiders).

The rest here.