Stills is missing Sunday's game with a quadriceps injury.
The Saints also are holding out fullback Erik Lorig (ankle) and safety Marcus Ball (hamstring).
Lorig, who had been expected to start, hasn't practiced since hurting his ankle during an intra-squad scrimmage Aug. 2.
Defensive tackle Corey Peters is inactive for Atlanta. Peters missed much of training camp during his rehabilitation from an Achilles tendon injury that ended his 2013 season.