Smith has been bothered by the sore hamstring for most of the season, but it appears to have worsened this week and he was listed as out on the injury report on Friday.

"He has been kind of fighting through it and he and the doctors and the trainers feel like it is just best that he gets that thing healed up," coach Brad Childress said after practice. "Hamstrings are funny things; some people can play the next week and some they linger."

Smith has been a physical presence on the back end of the Vikings defense and has emerged as a vocal team leader since signing as a free agent before last season. The seventh-year veteran has 21 tackles and two interceptions.

The Vikings defense is better equipped than most to handle the loss of a safety. Darren Sharper is the other starter and they also have veterans Tank Williams and Mike Doss on the roster.

"It definitely helps," cornerback Antoine Winfield said. "It would be a lot different if we had a guy who was coming in that was a rookie. Those guys have played in big games, have a lot of experience and know the defense. So I think they'll be able to go out there and perform well for us."

Childress said Williams and Doss, both of whom are coming back from serious knee injuries last year, will see time at safety against the Cowboys.

Williams said he is looking forward to his first action on defense since 2005 when he was with the Tennessee Titans. He missed all of last season with a knee injury and has played almost exclusively on special teams in the first five games this year.