Harrison Smith ruled out vs. Falcons

MINNEAPOLIS -- The Vikings have ruled Harrison Smith out for Sunday's game against the Falcons, meaning they'll try to contain Julio Jones and Atlanta's prolific passing attack without the help of their best safety.

Smith suffered a left knee injury last Sunday when he collided with cornerback Terence Newman in the first quarter of the Vikings' loss to the Green Bay Packers. He was listed as questionable on the team's injury report Friday after participating in practice on a limited basis, and said he was going to do his best to take care of his knee between then and Sunday.

After the Vikings' final walk-through Saturday, however, they downgraded Smith, who will not travel with the team to Atlanta.

Without Smith, the Vikings will have to work even harder to slow down the league's fifth-ranked passing attack in the Georgia Dome. Second-year safety Antone Exum could make his first career start on Sunday, as the Vikings look for a safety who can help in coverage.

Otherwise, the Vikings would turn to Robert Blanton, who started most of last season next to Smith before losing his job to Andrew Sendejo.

In any case, dealing with Jones, who leads the league with 89 catches, already figured to be a tough task. The absence of Smith -- who tied for third in the league with five interceptions a year ago -- could be a significant loss for the Vikings.

Vikings rookie cornerback Trae Waynes also was downgraded to out with an ankle injury that limited him in practice on Thursday and kept him out on Friday.