Sharper drilled Stewart in the head with his shoulder at the end of a 5-yard gain in the first quarter, causing Stewart to fumble. Stewart was on the ground for several minutes before walking off the field with the assistance of two members of Carolina's medical staff.
The Saints then won a replay challenge, giving them the ball on the fumble.
Stewart had rushed for 30 yards on five carries, matching his total from last week.
Stewart started for DeAngelo Williams, who missed his second straight game with a sprained left foot. That left Mike Goodson and Tyrell Sutton at running back.