FLOWERY BRANCH, Ga. — The Atlanta Falcons always talk about having a “next man up” mentality. This time, the next four men are up.

Dealing with the most serious rash of injuries that coach Mike Smith has ever encountered, the Falcons (1-1) returned to practice Wednesday looking to fill some major holes heading into a game against the unbeaten Dolphins.

“You never like to see guys go down,” quarterback Matt Ryan said. “But that’s part of the deal, part of the nature of the NFL. Guys are going to get nicked up. Other guys have to step up.”

The Falcons are more than nicked up. Two starters – defensive end Kroy Biermann and fullback Bradie Ewing – went down with season-ending injuries. Linebacker Sean Weatherspoon, the emotional leader of the defense, sustained a foot injury that will keep on the sideline for at least two months. Running back Stephen Jackson hobbled off with a hamstring problem and already has been ruled out of the Dolphins game, though the Falcons insist his injury isn’t nearly as serious as the others.

Three other key players – receiver Roddy White, cornerback Asante Samuel and tackle Sam Baker – didn’t practice.

“I don’t think there’s any shock factor,” Smith said. “In the NFL, guys are going to get injured.”

The Falcons also signed a couple of veterans, Jamar Chaney and Omar Gaither, to bolster their depth at linebacker.

On the offensive side, Jason Snelling is expected to line up at fullback when the Falcons go with a two-back alignment, as well as sharing time at halfback with Jacquizz Rodgers.

“These other teams we’re playing, they don’t care about any of that,” Snelling said. “It’s a next man up mentality that we have. We’re serious about it.”