Whether Turner can repeat his '08 is a smaller question mark than the other 3 rbs you have but that goes back to how strong your rb depth is. While you have 4 rbs (not counting Fargas) you have 8 wrs. And you have a flex position as an option where you can put either a rb or a wr. I would always put a rb in that spot if possible to have 3 rbs and 3 wrs starting. So I'd look to deal 1-2 wr's for a good rb, to improve your rb depth and balance things out, and then see what qbs are available as backups.
... there were just seven games last season in which he averaged 4.0 yards per carry or better. Five of the teams he did that against -- Detroit, Green Bay, Kansas City, Oakland and St. Louis -- aren't on the Falcons' 2009 schedule. Each of those five teams finished 26th or worse in terms of rushing yardage allowed per game. That leads me to wonder whether Turner's remarkable 2008 was less talent and more schedule.