Desmond Trufant ruled out against Vikings

Herm expects Keenum to falter against Falcons (0:43)

Herm Edwards predicts Atlanta will win in Week 13, becoming the first team to truly challenge Case Keenum and the Vikings offense. (0:43)

FLOWERY BRANCH, Ga. -- Atlanta Falcons cornerback Desmond Trufant, who remains in the concussion protocol, has been ruled out for Sunday's game against the Minnesota Vikings.

Trufant sustained a concussion in last week's win over the Tampa Bay Buccaneers during a helmet-to-helmet collision with teammate Keanu Neal. His absence means more opportunities for converted wide receiver C.J. Goodwin as the cornerback opposite Robert Alford.

The Falcons played without the 2015 Pro Bowler for the second half of last season after a pectoral injury landed him on injured reserve. Trufant was playing at a high level this season prior to the concussion.

While the Falcons lose Trufant, they will have nickelback Brian Poole, who has battled a back injury all week. Poole tested out his back during Friday's practice and was cleared after meeting with coach Dan Quinn and a member of the medical staff.

Poole appeared to be a little stiff during practice, however. If he suffers a setback, the Falcons could move free safety Ricardo Allen to nickelback, as they did last week. Rookie Damontae Kazee would then step in for Allen at free safety.

No matter who plays, the Falcons secondary will face quite a challenge against Vikings quarterback Case Keenum, the NFC's Offensive Player of the Month for November, and top wide receivers Adam Thielen and Stefon Diggs, who have combined for 1,603 yards and eight touchdowns on 110 catches.

Atlanta ranks eighth in the NFL in pass defense, allowing 207.9 yards per game.

The Falcons will get back two-time Pro Bowl running back Devonta Freeman, who missed the previous two games while recovering from a concussion. Freeman had a full practice all week and is ready to assume his normal workload with Tevin Coleman and Terron Ward behind him.