DeAngelo Williams had a season to remember in 2008. With 1515 rushing yards and a league-leading 18 rushing TDs, Williams powered many fantasy teams to championships last season. More amazingly, he did it in only 273 carries, which works out to a whopping 5.5 yds per carry average. Based on those numbers, DeAngelo Williams is likely to be drafted as a Top 5 fantasy running back.
Don't do it. Williams had an amazing season but it was a crazy, improbable, fluke of a season. He broke off 50+ yd touchdown runs. He caught defenses unaware. His team ran the ball a huge amount. None of those things are going to happen this season.
Williams is not going to average 5.5 yds per carry; there's no way any back can sustain that rate, especially not DeAngelo Williams. If you project him to have a reasonably-good 4.1 yds per carry average - with the same number of carries - it works out to 1,119 yds. A good season, but not a Top 5 season. In my rankings, not even a Top 10 season.
Next, he's not going to catch teams unaware again. Between Williams and teammate Jonathan (836 yds, 10 TD) Stewart, the entire NFL knows that the Panthers are running the ball. Teams will be focused on stopping them this season. Since there isn't a lot of fear when it comes to QB Jake Delhomme, teams will be very, very focused on stopping the run. They're likely be pretty good at stopping the run too.
Finally, the Panthers are going to have throw the ball more. Just as defenses know the Panthers will run and so will focus on stopping it, the Panthers know defenses will focus on stopping it and so will throw more. With Stewart ready to rumble, Carolina will rely less on Williams and more on Delhomme.
DeAngelo Williams should have a good season and he'll be a good fantasy RB. What he won't have is 1300 rushing yards or double digit TDs. Considering all the hype around him, I consider him a bust candidate this season.