Falcons linebacker Marquis Spruill suffered a torn ACL in his left knee and will be out for the season, coach Mike Smith said on Thursday.

The Falcons are set to open the exhibition season against the Miami Dolphins at 7 p.m. Friday at the Georgia Dome.

Spruill was a fifth-round pick and the 168th player taken in the draft. The speedy linebacker was expected to be a reserve and contribute on special teams. He went down after a play on Wednesday and was helped off the field by two trainers.

In addition to losing Spruill, wide receiver Drew Davis (left leg), safety Zeke Motta (neck), running back Steven Jackson (hamstring), linebacker Pat Angerer (concussion), Terren Jones (concussion), safety Dwight Lowery (concussion), defensive tackle Corey Peters (Achilles) and offensive tackle/guard Gabe Carimi (ankle) are not expected to play.

Also, rookie safety Dezmen Southward, who returned to practice on Wednesday from an knee injury, participated fully in Thursday’s practice.

“It was good to see him back out here doing some things on the field and not being with the trainers,” Smith said.