The Saints traded for the 6'1 230 LB before the 2008 season, and he's been a centerpiece of their defense since, going to Pro Bowls in 2009 and 2010.
In seven games this year, Vilma has 34 tackles and two pass deflections. His absence will be big blow for a mediocre New Orleans rush defense, which has allowed 119.7 yards a game this season, 17th in the NFL.
Atlanta will try to take advantage by featuring star RB Michael Turner, who has rushed for 692 yards and 7 TD's on 4.4 yards per carry this season. Tony Gonzalez, the Falcons star TE, could have a big game as well, as he should have more room to roam in the middle of the field.