Louis left the postgame locker room in a walking boot.
"I just got rolled up on, that's all," Lance said. "A little ankle sprain. I'll be fine, just rehab it and work at rehabbing it. I'll be alright. Definitely not (a season ending injury). I'll be back."
Backup center Chris Spencer replaced Louis at right guard for the remainder of the game. Spencer started 70 of 82 games at both center and guard for Seattle before signing a two-year contract with the Bears on July 31.
"I had a couple reps (at guard) this week, but that's about all," Spencer said. "I played very little guard at Seattle, only three games, I played the center really the whole time. But it wasn't a total shock. They told me if a guard went down you would go at both guard positions."
Edwin Williams, listed as the club's No. 2 right and left guard on the official depth chart, was a game day inactive on Sunday.
Meanwhile, wide receiver Roy Williams left the season opener with a groin injury he sustained on a 13-yard reception in the fourth quarter. The receiver appeared to tweak the groin muscle as he ran toward the Bears sideline trying to avoid a Falcons defender.
"It's good, I'll just get some treatment and see what happens for the week," Williams said. "I was trying to elude the corner and it just happened I guess."
Williams finished with four receptions for 55 yards.
Jeff Dickerson covers the Bears for ESPN 1000 and ESPNChicago.com.