FLOWERY BRANCH, Ga. -- Atlanta Falcons free safety Dwight Lowery, who has been working with the starters, suffered the third concussion of his NFL career during Friday night's practice, coach Mike Smith confirmed Saturday.
"Dwight, as I said last night, he had an injury to his head, and he is in the concussion protocol," Smith said. "We don't think it's very serious. But that's where he is right now."
Lowery, slated to step into the starting lineup alongside strong safety William Moore, suffered a season-ending concussion in Week 3 of last season while with the Jacksonville Jaguars. This is his fourth concussion since college.
"You're concerned on the first one I think just as much as the second or third," Smith said. "Dwight is a guy who has played a long time in this league. I think he knows his body pretty well. And, of course, he'll go through the league-mandated protocol before he goes back out on the field."
Lowery has 41 career starts in six previous seasons with the Jaguars and New York Jets.
"It doesn't affect much; it's part of the game," Moore said of Lowery's injury. "People go down, people get injured. All we do is come out and play with the people we've got. His injury, I don't feel like, is that serious. And he'll bounce back."
Lowery's immediate departure means the Falcons are significantly depleted at safety. Second-year player Zeke Motta is not expected to play this season coming off neck surgery, while rookie Dez Southward is out at least week after suffering a left knee injury during training camp.
Smith also did not rule out adding outside help.
"We would never discount making a roster move, if there's someone that we feel can help us," Smith said.
Second-year player Kemal Ishmael stepped into a starter's role alongside Moore in the interim. The Central Florida product primarily played on special teams last season.
"Kemal's had a good camp," defensive coordinator Mike Nolan said of Ishmael. "Kemal's done a nice job. ... He's made some good strides from a year ago. I know he's [10 pounds] lighter and he's moving a lot better. He's one of the guys that's been able to take advantage of some of the things with the front line being a little stouter, just from the standpoint of coming up and closing the gap."
The Falcons released veteran free safety Thomas DeCoud after the 2013 season. DeCoud started 15 games next to Moore last season, missing one contest due to a concussion.