Trufant had been holding out hope that he could play through the injury sustained in Week 9.
The loss of the fourth-year cornerback, Atlanta's premier defensive star, is a severe blow to the team's Super Bowl chances.
As impressive as the NFL's No. 1 offense has been this season, Dan Quinn's pass defense ranks dead-last in the league. Despite a significantly improved pass rush, the secondary has already allowed more passing touchdowns (25) through 11 games than they did all of last season.
With Trufant out of the mix, Quinn will need 2015 second-round pick Jalen Collins to step into a starting role, hoping he can hold his own against top receivers.
The Falcons have enough offensive firepower to keep winning shootouts throughout the regular season. Once the competition ramps up in January, though, the 32nd-ranked pass defense looms as a potential stumbling block.